R"EESE    LIBRARY 


UNIVERSITY    OF   CALIFORNIA 


Received : 

Accessions  No. 


Shelf  No. .  _ 


The  Solar  System. 


METEORIC  ASTRONOMY: 


A   TREATISE 


SHOOTING-STARS,  FIRE-BALLS, 


AEROLITES. 


BY 


DANIEL   KIRKWOOD,  LL.D. 

PROFESSOR     OF     MATHEMATICS     IN    WASHINGTON     AND    JEFFERSON     COLLEGE. 


PHILADELPHIA: 

J.    B.    LIPPINOOTT    &    CO. 

1867. 


Entered,  according  to  Act  of  Congress,  in  the  year  1867,  by 

DANIEL   KIRKWOOI),  LL.D., 

Ti>  the  Clerk's  Office  of  the  District  Court  of  the  United  States  for  the 
Western  District  of  Pennsylvania. 


K5" 


PREFACE. 


ARISTOTLE  and  other  ancient  writers  regarded  comets  as 
meteors  generated  in  the  atmosphere.  This  opinion  was 
generally  accepted,  even  by  the  learned,  until  the  observa 
tions  of  Tycho,  near  the  close  of  the  sixteenth  century, 
showed  those  mysterious  objects  to  be  more  distant  than 
the  moon,  thus  raising  them  to  the  dignity  of  celestial 
bodies.  An  achievement  somewhat  similar,  and  certainly 
no  less  interesting,  was  reserved  for  the  astronomers  of  the 
nineteenth  century.  This  was  the  great  discovery  that 
shooting- stars,  fire-balls,  and  meteoric  stones,  are,  like 
comets,  cosmical  bodies  moving  in  conic  sections  about  the 
sun.  DR.  HALLEY  was  the  first  to  foretell  the  return  of  a 
comet,  and  the  year  It 59  will  ever  be  known  in  history  as 
that  which  witnessed  the  fulfillment  of  his  prophecy.  But 
in  the  department  of  meteoric  astronomy,  a  similar  honor 
must  now  be  awarded  to  the  late  DR.  OLBERS.  Soon  after 
the  great  star-shower  of  1833  he  inferred  from  a  comparison 
of  recorded  facts  that  the  November  display  attains  a  max 
imum  at  intervals  of  thirty  three  or  thirty-four  years.  He 
accordingly  designated  1866  or  1861  as  the  time  of  its 
probable  return ;  and  the  night  of  November  13th  of  the 
former  year  must  always  be  memorable  as  affording  the 
first  verification  of  his  prediction.  On  that  night  several 
thousand  meteors  were  observed  in  one  hour  from  a  single 
station.  This  remarkable  display,  together  with  the  fact 
that  another  still  more  brilliant  is  looked  for  in  November, 
1861,  has  given  meteoric  astronomy  a  more  than  ordinary 
degree  of  interest  in  the  public  mind.  To  gratify,  in  some 


IV  PREFACE. 

measure,  the  curiosity  which  has  been  awakened,  by  pre 
senting  in  a  popular  form  the  principal  results  of  observa 
tion  and  study  in  this  new  field  of  research,  is  the  main 
design  of  the  following  work. 

The  first  two  chapters  contain  a  popular  view  of  what  is 
known  in  regard  to  the  star- showers  of  August  and  Novem 
ber,  and  also  of  some  other  epochs.  The  third  is  a  descrip 
tion,  in  chronological  order,  of  the  most  important  falls  of 
meteoric  stones,  together  with  the  phenomena  attending 
their  descent.  The  fourth  and  following  chapters  to  the 
eleventh  inclusive,  discuss  various  questions  in  the  theory 
of  meteors:  such,  for  instance,  as  the  relative  number  of 
aerolitic  falls  during  different  parts  of  the  day,  and  also  of 
the  year;  the  coexistence  of  the  different  forms  of  meteoric 
matter  in  the  same  rings  ;  meteoric  dust ;  the  stability  of 
the  solar  system ;  the  doctrine  of  a  resisting  medium ;  the 
extent  of  the  atmosphere  as  indicated  by  meteors ;  the  me 
teoric  theory  of  solar  heat ;  and  the  phenomena  of  variable 
and  temporary  stars.  The  twelfth  chapter  regards  the 
rings  of  Saturn  as  dense  meteoric  swarms,  and  accounts  for 
the  principal  interval  between  them.  The  thirteenth  pre 
sents  various  facts,  not  previously  noticed,  respecting  the 
asteroid  zone  between  Mars  and  Jupiter,  with  suggestions 
concerning  their  cause  or  explanation 

As  the  nebular  hypothesis  furnishes  a  plausible  account 
of  the  origin  of  meteoric  streams,  it  seemed  desirable  to  pre 
sent  an  intelligible  view  of  that  celebrated  theory.  This 
accordingly  forms  the  subject  of  the  closing  chapter. 

The  greater  part  of  the  following  treatise,  it  is  proper  to 
remark,  was  written  before  the  publication  (in  England)  of 
Dr.  Phipson's  volume  on  "  Meteors,  Aerolites,  and  Falling- 
stars."  The  author  has  had  that  work  before  him,  however, 
while  completing  his  manuscript,  and  has  availed  himself 
of  some  of  the  accounts  there  given  of  recent  phenomena. 

('ANONSBI'KU,  I'.\  ,  Nay,  18(57. 


CONTENTS. 


PAGE 
IN  TRODUCTION 7 

CHAPTER  I. 
The  Meteors  of  November  12th-14th 18 

CHAPTER  II. 
Other  Meteoric  Rings 26 

CHAPTER  III. 
Aerolites 35 

CHAPTER  IV. 
Conjectures  in  Regard  to  Meteoric  Epochs 50 


CHAPTER  V. 

Geographical  Distribution  of  Meteoric  Stones — Do  Aerolitic  Falls 
occur  more  frequently  by  Day  than  by  Night? — Do  Meteorites, 
Bolides,  and  the  matter  of  ordinary  Shooting-stars,  coexist  in 
the  same  Rings? 50 

CHAPTER  VI. 

Phenomena  supposed  to  be  Meteoric  —  Meteoric  Dust  —  Dark 
Days 65 

CHAPTER  VII. 

Researches   of    Reichenbach — Theory  of    Meteors — Stability   of 

the  Solar  System — Doctrine  of  a  Resisting  Medium 74 

1*  (v) 


VI  CONTENTS. 


CHAPTER  VIII. 

PAOE 

Does  the  Number  of  Aerolitic  Falls  vary  with  the  Earth's  Distance 
from  the  Sun? — Relative  Numbers  observed  in  the  Forenoon 
and  Afternoon — Extent  of  the  Atmosphere  as  indicated  by 
Meteors 70 

CHAPTER  IX. 
The  Meteoric  Theory  of  Solar  Heat 84 

CHAPTER  X. 

Will  the  Meteoric  Theory  account  for  the  Phenomena  of  Vari 
able  and  Temporary  Stars? 92 

CHAPTER  XL 
The  Lunar  and  Solar  Theories  of  the  Origin  of  Aerolites 9G 

CHAPTER  XII. 
The  Rings  of  Saturn 102 

CHAPTER  XIII. 
The  Asteroid  Ring  between  Mars  and  Jupiter 105 

CHAPTER  XIV. 
Origin  of  Meteors — The  Nebular  Hypothesis 112 

APPKNDIX .  123 


INTRODUCTION. 


A  GENERAL  VIEW  OF  THE  SOLAR  SYSTEM. 

THE  SOLAR  SYSTEM  consists  of  the  sun,  together  with 
the  planets  and  comets  which  revolve  around  him  as  the 
center  of  their  motions.  The  sun  is  the  great  controlling 
orb  of  this  system,  and  the  source  of  light  and  heat  to  its 
various  members.  Its  magnitude  is  one  million  four  hun 
dred  thousand  times  greater  than  that  of  the  earth,  and  it 
contains  more  than  seven  hundred  times  as  much  matter 
as  all  the  planets  put  together. 

MERCURY  is  the  nearest  planet  to  the  sun  ;  its  mean  dis 
tance  being  about  thirty-seven  millions  of  miles.  Its  diam 
eter  is  about  three  thousand  miles,  and  it  completes  its 
orbital  revolution  in  88  days. 

YENUS,  the  next  member  of  the  system,  is  sometimes  our 
morning  and  sometimes  our  evening  star.  Its  magnitude 
is  almost  exactly  the  same  as  that  of  the  earth.  It  revolves 
round  the  sun  in  225  days. 

THE  EARTH  is  the  third  planet  from  the  sun  in  the  order 
of  distance;  the  radius  of  its  orbit  being  about  ninety-five 
millions  of  miles.  It  is  attended  by  one  satellite — the  moon 
— the  diameter  of  which  is  2160  miles. 

MARS  is  the  first  planet  exterior  to  the  earth's  orbit.  It 
is  considerably  smaller  than  the  earth,  and  has  no  satellite. 
It  revolves  round  the  sun  in  687  days. 

( vii ) 


Vlil  INTRODUCTION. 

THE  ASTEROIDS. — Since  the  commencement  of  the 
present  century  a  remarkable  zone  of  telescopic  planets  has 
been  discovered  immediately  exterior  to  the  orbit  of  Mars. 
These  bodies  are  extremely  small ;  some  of  them  probably 
containing  less  matter  than  the  largest  mountains  on  the 
earth's  surface.  More  than  ninety  members  of  the  group 
are  known  at  present,  and  the  number  is  annually  in 
creasing. 

JUPITER,  the  first  planet  exterior  to  the  asteroids,  is 
nearly  five  hundred  millions  of  miles  from  the  sun,  and  re 
volves  round  him  in  a  little  less  than  twelve  years.  This 
planet  is  ninety  thousand  miles  in  diameter  and  contains 
more  than  twice  as  much  matter  as  all  the  other  planets, 
primary  and  secondary,  put  together.  Jupiter  is  attended 
by  four  moons  or  satellites. 

SATURN  is  the  seventh  planet  in  the  order  of  distance- 
counting  the  asteroids  as  one.  Its  orbit  is  about  four  hun 
dred  millions  of  miles  beyond  that  of  Jupiter.  This  planet 
is  attended  by  eight  satellites,  and  is  surrounded  by  three 
broad,  flat  rings.  Saturn  is  seventy-six  thousand  miles  in 
diameter,  and  its  mass  or  quantity  of  matter  is  more  than 
twice  that  of  all  the  other  planets  except  Jupiter. 

URANUS  is  at  double  the  distance  of  Saturn,  or  nineteen 
times  that  of  the  earth.  Its  diameter  is  about  thirty-five 
thousand  miles,  and  its  period  of  revolution,  eighty-four 
years.  It  is  attended  by  four  satellites. 

NEPTUNE  is  the  most  remote  known  member  of  the  sys 
tem;  its  distance  being  nearly  three  thousand  millions  of 
miles.  It  is  somewhat  larger  than  Uranus ;  has  certainly 
one  satellite,  and  probably  several  more.  Its  period  is 
about  one  hundred  and  sixty-five  years.  A  cannon-ball 
flying  at  the  rate  of  five  hundred  miles  per  hour  would  not 
reach  the  orbit  of  Neptune  from  the  sun  in  less  than  six 
hundred  and  eighty  years. 

These  planets  all  move  round  the  sun  in  the  same  direr- 


INTRODUCTION.  IX 

tion — from  west  to  east.  Their  motions  are  nearly  circular, 
and  also  nearly  in  the  same  plane.  Their  orbits,  except 
that  of  Neptune,  are  represented  in  the  frontispiece.  It  is 
proper  to  remark,  however,  that  all  representations  of  the 
solar  system  by  maps  and  planetariums  must  give  an  ex 
ceedingly  erroneous  view  either  of  the  magnitudes  or  dis 
tances  of  its  various  members.  If  the  earth,  for  instance, 
be  denoted  by  a  ball  half  an  inch  in  diameter,  the  diameter 
of  the  sun,  according  to  the  same  scale  (sixteen  thousand 
miles  to  the  inch),  will  be  between  four  and  five  feet;  that 
of  the  earth's  orbit,  about  one  thousand  feet;  while  that  of 
Neptune's  orbit  will  be  nearly  six  miles.  To  give  an  accu 
rate  representation  of  the  solar  system  at  a  single  view  is 
therefore  plainly  impracticable. 

COMETS. — The  number  of  comets  belonging  to  our  system 
is  unknown.  The  appearance  of  more  than  seven  hundred 
has  been  recorded,  and  of  this  number,  the  elements  of 
about  two  hundred  have  been  computed.  They  move  in 
very  eccentric  orbits — some,  perhaps,  in  parabolas  or  hyper 
bolas. 

THE  ZODIACAL  LIGHT  is  a  term  first  applied  by  Dominic 
Cassini,  in  1683,  to  a  faint  nebulous  aurora,  somewhat  re 
sembling  the  milky- way,  apparently  of  a  conical  or  lenticu 
lar  form,  having  its  base  toward  the  sun,  and  its  axis  nearly 
in  the  direction  of  the  ecliptic.  The  most  favorable  time 
for  observing  it  is  when  its  axis  is  most  nearly  perpendicu 
lar  to  the  horizon.  This,  in  our  latitudes,  occurs  in  March 
for  the  evening,  and  in  October  for  the  morning.  The  angu 
lar  distance  of  its  vertex  from  the  sun  is  frequently  seventy 
or  eighty  degrees,  while  sometimes,  though  rarely  (except 
within  the  tropics),  it  exceeds  even  one  hundred  degrees. 

The  zodiacal  light  is  probably  identical  with  the  meteor 
called  trabes  by  Pliny  and  Seneca.  It  was  noticed  in  the 
latter  part  of  the  sixteenth  century  by  Tycho  Brahe,  who 
''considered  it  to  be  an  abnormal  spring-evening  twilight." 


X  INTRODUCTION. 

It  was  described  by  Descartes  about  the  year  1630,  and 
again  by  Childrey  in  1661.  The  first  accurate  description 
of  the  phenomenon  was  given,  however,  by  Cassini.  This 
astronomer  supposed  the  appearance  to  be  produced  by  the 
blended  light  of  an  innumerable  multitude  of  extremely 
small  planetary  bodies  revolving  in  a  ring  about  the  sun. 
The  appearance  of  the  phenomenon  as  seen  in  this  country 
is  represented  in  Fig.  2. 


For  general  readers  it  may  not  be  improper  to  premise 
the  following  explanations : 

Meteors  are  of  two  kinds,  cosmical  and  terrestrial:  the 
former  traverse  the  interplanetary  spaces  ;  the  latter  orig 
inate  in  the  earth's  atmosphere. 

Bolides  is  a  general  name  for  meteoric  fire-balls  of 
greater  magnitude  than  shooting-stars. 

The  period  of  a  planet,  comet,  or  meteor  is  the  time 
which  it  occupies  in  completing  one  orbital  revolution. 


INTRODUCTION. 


XI 


The  motion  of  a  heavenly  body  is  said  to  be  direct  when 
it  is  from  west  to  east;  and  retrograde  when  it  is  from 
east  to  west. 

Encke's  Hypothesis  of  a  Resisting  Medium. — The  time 
occupied  by  Encke's  comet  in  completing  its  revolution 
about  the  sun. is  becoming  less  and  less  at  each  successive 
return.  Professor  Encke  explains  this  fact  by  supposing 
the  interplanetary  spaces  to  be  filled  with  an  extremely 
rare  fluid,  the  resistance  of  which  to  the  cometary  motion 
produces  the  observed  contraction  of  the  orbit. 


METEORIC   ASTRONOMY. 


CHAPTER   I. 

SHOOTING-STARS. 

I.  The  Meteors  of  November  12th-14th. 

ALTHOUGH  shooting- stars  have  doubtless  been 
observed  in  all  ages  of  the  world,  they  have  never, 
until  recently,  attracted  the  special  attention  of 
scientific  men.  The  first  exact  observations  of  the 
phenomena  were  undertaken,  about  the  close  of  the 
last  century,  by  Messrs.  Brandes  and  Benzenberg. 
The  importance,  however,  of  this  new  department 
of  research  was  not  generally  recognized  till  after 
the  brilliant  meteoric  display  of  November  13th,  1833. 
This  shower  of  fire  can  never  be  forgotten  by  those 
who  witnessed  it.*  The  display  was  observed  from 
the  "West  Indies  to  British  America,  and  from  60° 
to  100°  west  longitude  from  Greenwich.  Captain 
Hammond,  of  the  ship  Restitution,  had  just  arrived 
at  Salem,  Massachusetts,  where  he  observed  the 
phenomenon  from  midnight  till  daylight.  He 

*  For  a  full  description,  see  Silliman's  Journal  for  January  and 
April,  1834  (Prof.  Olmsted's  article).      Also  a  valuable  paper,  in 
^the  July  No.  of  the  same  year,  by  Prof.  Twining. 

2  (13) 


14  METEORIC    ASTRONOMY. 

noticed  with  astonishment  that  precisely  one  year 
before,  viz.,  on  the  13th  of  November,  1832,  he  had 
observed  a  similar  appearance  (although  the  meteors 
were  less  numerous)  at  Mocha,  in  Arabia.  It  was 
soon  found,  moreover,  as  a  further  and  most  remark 
able  coincidence,  that  an  extraordinary  fall  of  meteors 
had  been  witnessed  on  the  12th  of  November,  1799. 
This  was  seen  and  described  by  Andrew  Ellicott, 
Esq.,  who  was  then  at  sea  near  Cape  Florida.  It 
was  also  observed  in  Cumana,  South  America,  by 
Humboldt,  who  states  that  it  was  "simultaneously 
seen  in  the  new  continent,  from  the  equator  to  New 
Herrnhut,  in  Greenland  (lat.  64°  14'),  and  between 
46°  and  82°  longitude." 

This  wonderful  correspondence  of  dates  excited  a 
very  lively  interest  throughout  the  scientific  world. 
It  was  inferred  that  a  recurrence  of  the  phenomenon 
might  be  expected,  and  accordingly  arrangements 
were  made  for  systematic  observations  on  the  12th, 
13th,  and  14th  of  November.  The  periodicity  of 
the  shower  was  thus,  in  a  very  short  time,  placed 
wholly  beyond  question.  The  examination  of  old 
historical  records  led  to  the  discovery  of  at  least  12 
appearances  of  the  November  shower  previous  to 
the  great  fall  of  1833.  The  descriptions  of  these 
phenomena  will  be  found  collected  in  an  interesting 
article  by  Prof.  H.  A.  Newton,  in  the  American  Jour 
nal  of  Science  and  Arts,  for  May,  1864.  They  occurred 
in  the  years  902,  931,  934,  1002,  1101,  1202,  1366, 
1533,  1602,  1698,  1799,  and  1832.  Besides  these  12 
enumerated  by  Professor  Newton  as  "the  predeces 
sors  of  the  great  exhibition  on  the  morning  of  No 
vember  13th,  1833,"  we  find  6  others,  less  distinctly 


SHOOTING-STARS.  15 

marked,  in  the  catalogue  of  M.  Quetelet.*  These 
were  in  the  years  1787,  1818,  1822,  1823,  1828,  and 
1831.  From  1833  to  1849,  inclusive,  Quetelet's 
catalogue  indicates  11  partial  returns  of  the  Novem 
ber  shower;  making  in  all,  up  to  the  latter  date,  29. 
In  1835,  November  13th,  a  straw  roof  was  set  on  lire 
by  a  meteoric  fire-ball,  in  the  department  de  1'Aine, 
France.  On  the  12th  of  November,  1837,  "at  8 
o'clock  in  the  evening,  the  attention  of  observers  in 
various  parts  of  Great  Britain  was  directed  to  a 
bright  luminous  body,  apparently  proceeding  from 
the  North,  which,  after  making  a  rapid  descent,  in 
the  manner  of  a  rocket,  suddenly  burst,  and  scatter 
ing  its  particles  into  various  beautiful  forms,  vanished 
in  the  atmosphere.  This  was  succeeded  by  others 
all  similar  to  the  first,  both  in  shape  and  the  manner 
of  its  ultimate  disappearance.  The  whole  display 
terminated  at  ten  o'clock,  when  dark  clouds,  which 
continued  up  till  a  late  hour,  overspread  the  earth, 
preventing  any  further  observations." — Milner's  Gal 
lery  of  Nature,  p.  142. 

In  1838,  November  12th-13th,  meteors  were 
observed  in  unusual  numbers  at  Vienna.  One  of 
extraordinary  brilliancy,  having  an  apparent  magni 
tude  equal  to  that  of  the  full  moon,  was  seen  near 
Cherburg. 

On  several  other  returns  of  the  November  epoch 
the  number  of  meteors  observed  has  been  greater 
than  on  ordinary  nights;  the  distinctly  marked 
exhibitions,  however,  up  to  1866,  have  all  been 
enumerated. 

*  Physique  du  Globe,  Chap.  IV. 


16  METEORIC  ASTRONOMY. 

THE  SHOWER  OF  NOVEMBER  14,  1866. 

The  fact  that  all  great  displays  of  the  November 
meteors  have  taken  place  at  intervals  of  thirty- three 
or  thirty-four  years,  or  some  multiple  of  that  period, 
had  led  to  a  general  expectation  of  a  brilliant  shower 
in  1866.  In  this  country,  however,  the  public  curi 
osity  was  much  disappointed.  The  numbers  seen 
were  greater  than  on  ordinary  nights,  but  not  such 
as  would  have  attracted  any  special  attention.  The 
greatest  number  recorded  at  any  one  station  was  seen 
at  New  Haven,  by  Prof.  Newton.  On  the  night  of 
the  12th,  694  were  counted  in  five  hours  and  twenty 
minutes,  and  on  the  following  night,  881  in  five 
hours.  This  was  about  six  times  the  ordinaiy  num 
ber.  A  more  brilliant  display  was,  however,  wit 
nessed  in  Europe.  Meteors  began  to  appear  in 
unusual  frequency  about  eleven  o'clock  on  the  night 
of  the  13th,  and  continued  to  increase  with  great 
rapidity  for  more  than  two  hours;  the  maximum 
being  reached  a  little  after  one  o'clock.  The  Edin 
burgh  Scotsman,  of  November  14th,  contains  a  highly 
interesting  description  of  the  phenomenon  as  ob 
served  at  that  city.  "Standing  on  the  Calton  Hill, 
and  looking  westward,"  the  editor  remarks, — "with 
the  Observatory  shutting  out  the  lights  of  Prince's 
Street — it  was  easy  for  the  eye  to  delude  the  imagin 
ation  into  fancying  some  distant  enemy  bombarding 
Edinburgh  Castle  from  long  range;  and  the  occa 
sional  cessation  of  the  shower  for  a  few  seconds,  only 
to  break  out  again  with  more  numerous  and  more 
brilliant  drops  of  fire,  served  to  countenance  this 
fancy.  Again,  turning  eastward,  it  was  possible  now 


SHOOTING-STARS. 

and  then  to  catch  broken  glimpses  of  the  train  of 
one  of  the  meteors  through  the  grim  dark  pillars  of 
that  ruin  of  most  successful  manufacture,  the  Na 
tional  Monument;  and  in  fact  from  no  point  in  or 
out  of  the  city  was  it  possible  to  watch  the  strange 
rain  of  stars,  pervading  as  it  did  all  points  of  the 
heavens,  without  pleased  interest,  and  a  kindling  of 
the  imagination,  and  often  a  touch  of  deeper  feeling 
that  bordered  on  awe.  The  spectacle,  of  which  the 
loftiest  and  most  elaborate  description  could  but  be 
at  the  best  imperfect — which  truly  should  have  been 
seen  to  be  imagined — will  not  soon  pass  from  the 
memories  of  those  to  whose  minds  were  last  night 
presented  the  mysterious  activities  and  boundless 
fecundities  of  that  universe  of  the  heavens,  the  very 
unchangeableness  of  whose  beauty  has  to  many  made 
it  monotonous  and  of  no  interest." 

The  appearance  of  the  phenomenon,  as  witnessed 
at  London,  is  minutely  described  in  the  Times  of 
November  15th.  The  shower  occurred  chiefly  be 
tween  the  hours  of  twelve  and  two.  About  one 
o'clock  a  single  observer  counted  200  in  two  min 
utes.  The  whole  number  seen  at  Greenwich  was 
8485.  The  shower  was  also  observed  in  different 
countries  on  the  continent. 

The  Meteors  of  1866  compared  with  those  of  former 
Displays. 

The  star  shower  of  1866  was  much  inferior  to  those 
of  1799  and  1833.*  With  these  exceptions,  however, 

*  Professor  Olmstcd  estimated  the  number  of  meteors,  visible  at 
New  Haven,  during  the  night  of  November  12ih-13th,  18^3,  at 
240,000. 

2* 


18  METEORIC    ASTRONOMY. 

it  has,  perhaps,  been  scarcely  surpassed  during  the 
last  500  years.  Historians  represent  the  meteors  of 
902  as  innumerable,  and  as  moving  like  rain  in  all 
possible  directions.*  The  exhibition  of  1202  was 
no  less  magnificent.  The  stars,  it  is  said,  were  seen 
to  dash  against  each  other  like  swarms  of  locusts; 
the  phenomenon  lasting  till  daybreak. f  The  shower 
of  1366  is  thus  described  in  a  Portuguese  chronicle, 
quoted  by  Humboldt:  "In  the  year  1366,  twenty- 
two  days  of  the  month  of  October  being  past,  three 
months  before  the  death  of  the  king,  Dom  Pedro 
(of  Portugal),  there  was  in  the  heavens  a  movement 
of  stars,  such  as  men  never  before  saw  or  heard  of. 
At  midnight,  and  for  some  time  after,  all  the  stars 
moved  from  the  east  to  the  west;  and  after  being 
collected  together,  they  began  to  move,  some  in  one 
direction,  and  others  in  another.  And  afterward 
they  fell  from  the  sky  in  such  numbers,  and  so  thickly 
together,  that  as  they  descended  low  in  the  air,  they 
seemed  large  and  fiery,  and  the  sky  and  the  air 
seemed  to  be  in  flames,  and  even  the  earth  appeared 
as  if  ready  to  take  fire.  That  portion  of  the  sky 
where  there  were  no  stars,  seemed  to  be  divided 
into  many  parts,  and  this  lasted  for  a  long  time." 
The  following  is  Humboldt's  description  of  the 

*  Conde  says,  "there  were  seen,  as  it  were  lances,  an  infinite 
number  of  stars,  which  scattered  themselves  like  rain  to  the  right 
and  left,  and  that  year  was  called  'the  year  of  stars.' :' 

f  In  1202,  "on  the  last  day  of  Muharrem,  stars  shot  hither  and 
thither  in  the  heavens,  eastward  and  westward,  and  flew  against  one 
another  like  a  scattering  swarm  of  locusts,  to  the  right  and  left;  this 
phenomenon  lasted  until  daybreak;  people  were  thrown  into  con 
sternation,  and  cried  to  God  the  Most  High  with  confused  clamor." 
—Quoted  by  Prof.  Newton,  in  Silliman's  Journal,  May,  1864. 


SHOOTING-STARS.  19 

shower  of  1799,  as  witnessed  by  himself  and  Bon- 
pland,  in  Cumana,  South  America:  "From  half 
after  two,  the  most  extraordinary  luminous  meteors 

were  seen  toward  the  east Thousands  of  bolides 

and  falling  stars  succeeded  each  other  during  four 
hours.  They  filled  a  space  in  the  sky  extending  from 
the  true  east  30°  toward  the  north  and  south.  In  an 
amplitude  of  60°  the  meteors  were  seen  to  rise  above 
the  horizon  at  E.  N.  E.  and  at  E.,  describe  arcs  more 
or  less  extended,  and  fall  toward  the  south,  after 
having  followed  the  direction  of  the  meridian.  Some 
of  them  attained  a  height  of  40°,  and  all  exceeded 

25°  or  30° Mr.  Bonpland  relates,  that  from  the 

beginning  of  the  phenomenon  there  was  not  a  space 
in  the  firmament  equal  in  extent  to  three  diameters 
of  the  moon,  that  was  not  filled  at  every  instant  with 

bolides  and   falling-stars The  Guaiqueries  in 

the  Indian  suburb  came  out  and  asserted  that  the 
firework  had  begun  at  one  o'clock The  phe 
nomenon  ceased  by  degrees  after  four  o'clock,  and 
the  bolides  and  falling-stars  became  less  frequent; 
but  we  still  distinguished  some  toward  the  northeast 

CD 

a  quarter  of  an  hour  after  sunrise." 

DISCUSSION    OF    THE    PHENOMENA. 

Since  the  memorable  display  of  November  13th, 
1833,  the  phenomena  of  shooting-stars  have  been 
observed  and  discussed  by  B ramies,  Benzenberg, 
Gibers,  Saigey,  Heis,  Glmsted,  Herrick,  Twining, 
Newton,  Greg,  and  many  others.  In  the  elaborate 
paper  of  Professor  Glmsted,  it  was  shown  that  the 
meteors  had  their  origin  at  a  distance  of  more  than 


20  METEORIC    ASTRONOMY. 

2000  miles  from  the  earth's  surface;  that  their  paths 
diverged  from  a  common  point  near  the  star  Gamma 
Leonis ;  that  in  a  number  of  instances  they  became 
visible  about  80  miles  from  the  earth's  surface ;  that 
their  velocity  was  comparable  to  that  of  the  earth  in 
its  orbit;  and  that  in  some  cases  their  extinction 
occurred  at  an  elevation  of  30  miles.  It  was  in 
ferred,  moreover,  that  they  consisted  of  combustible 
matter  which  took  fire  and  was  consumed  in  passing 
through  the  atmosphere;  that  this  matter  was  de 
rived  from  a  nebulous  body  revolving  round  the  sun 
in  an  elliptical  orbit,  but  little  inclined  to  the  plane 
of  the  ecliptic;  that  its  aphelion  was  near  that  point 
of  the  earth's  orbit  through  wThich  we  annually  pass 
about  the  13th  of  November — the  perihelion  being 
a  little  within  the  orbit  of  Mercury;  and  finally  that 
its  period  was  about  one-half  that  of  the  earth.  Dr. 
Olmsted  subsequently  modified  his  theory,  having 
been  led  by  further  observations  to  regard  the  zodi 
acal  light  as  the  nebulous  body  from  which  the 
shooting-stars  are  derived.  The  latter  hypothesis 
was  also  adopted  by  the  celebrated  Biot. 

The  fact  that  the  position  of  the  radiant  point  does 
not  change  with  the  earth's  rotation,  places  the  cos- 
mica!  origin  of  the  meteors  wholly  beyond  question. 
The  theory  of  a  closed  ring  of  nebulous  matter  re 
volving  round  the  sun  in  an  elliptical  orbit  which 
intersects  that  of  the  earth,  affords  a  simple  and 
satisfactory  explanation  of  the  phenomena.  This 
theory  was  adopted  by  Humboldt,  Arago,  and  others, 
shortly  after  the  occurrence  of  the  meteoric  shower 
of  1833.  That  the  body  which  furnishes  the  mate 
rial  of  these  meteors  moves  in  a  closed  or  elliptical 


SHOOTING-STARS.  21 

orbit  is  evident  from  the  periodicity  of  the  shower.  It 
is  also  manifest  from  the  partial  recurrence  of  the  phe 
nomenon  from  year  to  year,  that  the  matter  is  dif 
fused  around  the  orbit;  while  the  extraordinary  falls 
of  1833,  1799,  1366,  and  1202,  prove  the  diffusion  to 
be  far  from  uniform. 

ELEMENTS  OF  THE  ORBIT. 

Future  observations,  it  may  be  hoped,  will  ulti 
mately  lead  to  an  accurate  determination  of  the 
elements  of  this  ring:  many  years,  however,  will 
probably  elapse  before  all  the  circumstances  of  its 
motion  can  be  satisfactorily  known.  Professor  New 
ton,  of  Yale  College,  has  led  the  way  in  an  able  dis 
cussion  of  the  observations.*  He  has  shown  that 
the  different  parts  of  the  ring  are,  in  all  probability, 
of  very  unequal  density;  that  the  motion  is  retro 
grade;  and  that  the  time,  during  which  the  meteors 
complete  a  revolution  about  the  sun,  must  be  limited 
to  one  of  five  accurately  determined  periods,  viz. : 
180-05  days,  185-54  days,  354-62  days,  376'5  days,  or 
33-25  years.  He  makes  the  inclination  of  the  ring  to 
the  ecliptic  about  17°.  The  five  periods  specified,  he 
remarks,  u  are  not  all  equally  probable.  Some  of  the 
members  of  the  group  which  visited  us  last  November 
[1863]  gave  us  the  means  of  locating  approximately 
the  central  point  of  the  region  from  which  the  paths 
diverge.  Mr.  G.  A.  Nolen  has,  by  graphical  processes 
specially  devised  for  the  purpose,  found  its  longitude 
to  be  142°,  and  its  latitude  8°  30'.'  This  longitude 

*  Am.  Journ.  of  Sci.  and  Arts,  May  and  July,  1864. 


22  METEORIC    ASTRONOMY. 

is  very  nearly  that  of  the  point  in  the  ecliptic  toward 
which  the  earth  is  moving.  Hence  the  point  from 
which  the  ahsolute  motion  of  the  bodies  is  directed 
(being  in  a  great  circle  through  the  other  two  points) 
has  the  same  longitude.  The  absolute  motion  of 
each  meteor,  then,  is  directed  very  nearly  at  right 
angles  to  a  line  from  it  to  the  sun,  the  deviation  be 
ing  probably  not  more  than  two  or  three  degrees. 

"Now,  if  in  one  year  the  group  make  2±33123  revo 
lutions,  there  is  only  a  small  portion  of  the  orbit  near 
the  aphelion  which  fulfills  the  above  condition.  In 
like  manner,  if  the  periodic  time  is  33-25  years,  only 
a  small  portion  of  the  orbit  near  the  perihelion  ful 
fills  it.  On  the  other  hand,  if  the  annual  motion  is 
1±3-^  revolutions,  the  required  condition  is  answered 
through  a  large  part  of  the  orbit.  Inasmuch  as  no 
reason  appears  why  the  earth  should  meet  a  group 
near  its  apsides  rather  than  elsewrhere,  we  must  regard 
it  as  more  probable  that  the  group  makes  in  one 
year  either  l+g-^,  or  1 — ~  revolutions." 

Professor  Newton  concludes  that  the  third  of  the 
above-mentioned  periods,  viz.,  354  62  days,  combines 
the  greatest  amount  of  probability  of  being  the  true 
one.  We  grant  the  force  of  the  reasons  assigned  for 
its  adoption.  At  least  one  consideration,  however, 
in  favor  of  the  long  period  of  33-25  years  is  by  no 
means  destitute  of  weight:  of  nearly  100  known 
bodies  which  revolve  about  the  sun  in  orbits  of  small 
eccentricity,  not  one  has  a  retrograde  motion.  Now 
if  this  striking  fact  has  resulted  from  a  general  cause, 
how  shall  we  account  for  the  backward  motion  of  a 
meteoric  ring,  in  an  orbit  almost  circular,  and  but 
little  inclined  to  the  plane  of  the  ecliptic?  In  such 


SHOOTING-STARS.  23 

a  case,  is  not  the  preponderance  of  probability  in 
favor  of  the  longer  period? 

A  revolution  in  33-25  years  corresponds  to  an 
ellipse  whose  major  axis  is  20-6.  Consequently  the 
aphelion  distance  would  be  somewhat  greater  than 
the  mean  distance  of  Uranus.  It  may  also  be  worthy 
of  note,  that  five  periods  of  the  ring  would  be  very 
nearly  equal  to  two  of  Uranus. 

The  Monthly  Notices  of  the  Eoyal  Astronomical 
Society  for  December,  1866,  and  January,  1867,  con 
tain  numerous  articles  on  the  star  shower  of  Novem 
ber  13th-14th,  1866.  Sir  John  Herschel  carefully 
observed  the  phenomena,  and  his  conclusions  in 
regard  to  the  orbit  are  confirmatory  of  those  of  Pro 
fessor  Newton.  "We  are  constrained  to  conclude," 
he  remarks,  "  that  the  true  line  of  direction,  in  space 
of  each  meteor's  flight,  lay  in  a  plane  at  right  angles 
to  the  earth's  radius  vector  at  the  moment;  and  that 
therefore,  except  in  the  improbable  assumption  that 
the  meteor  was  at  that  moment  in  perihelia  or  in  ap- 
helio,  its  orbit  would  not  deviate  greatly  from  the 
circular  form."  The  question  is  one  to  be  decided 
by  observation,  and  the  only  meteor  whose  track 
and  time  of  flight  seem  to  have  been  well  observed, 
is  that  described  by  Professor  Newton  in  Silliman's 
Journal  for  January,  1867,  p.  86.  The  velocity  in 
this  case,  if  the  estimated  time  of  flight  was  nearly 
correct,  was  inconsistent  with  the  theory  of  a  circular 
orbit. 

It  is  also  worthy  of  notice  that  Dr.  Oppolzer's 
^elements  of  the  first  cornet  of  1866  resemble,  in  a 
remarkable  manner,  those  of  the  meteoric  ring,  sup 
posing  the  latter  to  have  a  period  of  about  33 J  years. 


24  METEORIC    ASTRONOMY. 

Schiaparelli's  elements  of  the  November  ring,  and 
Oppolzer's  elements  of  the  comet  of  1866,  are  as 
follows: 

November  Comet  of 

Meteors.  1866. 

Longitude  of  perihelion 56°  25'  60°  28' 

Longitude  of  ascending  node 231    28  231    26 

Inclination 17    44  17    18 

Perihelion  distance 0-9873  0-9765 

Eccentricity 0-9046  0-9054 

Semi-axis  major 10-3400  10-3240 

Period,  in  years 33-2500  33-1760 

Motion Retrograde.  Retrograde. 

It  seems  very  improbable  that  these  coincidences 
should  be  accidental.  Leverrier  and  other  astrono 
mers  have  found  elements  of  the  meteoric  orbit  agree 
ing  closely  with  those  given  by  Schiaparelli.  Should 
the  identity  of  the  orbits  be  fully  confirmed,  it  will 
follow  that  the  comet  of  1866  is  a  very  large  meteor  of 
the  November  stream. 

The  researches  of  Professor  C.  Bruhns,  of  Leipzig, 
in  regard  to  this  group  of  meteors  afford  a  probable 
explanation  of  the  division  of  Biela's  comet — a  phe 
nomenon  which  has  greatly  perplexed  astronomers 
for  the  last  twenty  years.  Adopting  the  period  of 
331  years,  Professor  Bruhns  finds  that  the  comet 
passed  extremely  near,  and  probably  through  the  me 
teoric  ring  near  the  last  of  December,  1845.  It  is 
easy  to  perceive  that  such  a  collision  might  produce 
the  separation  soon  afterward  observed. 

As  the  comet  of  Biela  makes  three  revolutions  in 
twenty  years,  it  was  again  at  this  intersection,  or 
approximate  intersection  of  orbits  about  the  end  of 
1865.  But  although  the  comet's  position,  with  re- 


Hg.  3. 


SHOOTING-STARS.  25 

spect  to  the  earth,  was  the  same  as  in  1845-6,  and 
although  astronomers  watched  eagerly  for  its  ap 
pearance,  their  search  was  unsuccessful.  In  short, 
the  comet  is  lost.  The  denser  portion  of  the  meteoric 
stream  was  then  approaching  its  perihelion.  A  por 
tion  of  the  arc  had  even  passed  that  point,  as  a 
meteoric  shower  was  observed  at  Greenwich  on  the 
13th  of  November,  1865.*  The  motion  of  the  me 
teoric  stream  is  retrograde;  that  of  the  comet,  direct. 
Did  the  latter  plunge  into  the  former,  and  was  its 
non  appearance  the  result  of  such  collision  and  en 
tanglement? 

*  The  stream  or  arc  of  meteors  is  several  years  in  passing  its  node. 
The  first  indication  of  the  approach  of  the  display  of  1866  was  the 
appearance  of  meteors  in  unusual  numbers  at  Malta,  on  the  13th  of 
November,  1864.  The  great  length  of  the  arc  is  indicated,  more 
over,  by  the  showers  of  931  and  934. 


CHAPTER   II. 

OTHER    METEOEIC    KINGS. 

II.  The  Meteors  of  August  Gth-llth. 

MUSCIIENBROEK,  in  his  Introduction  to  Natural  Philos 
ophy,  published  in  1762,  called  attention  to  the  fact 
that  shooting-stars  are  more  abundant  in  August 
than  in  any  other  part  of  the  year.  The  annual 
periodicity  of  the  maximum  on  the  9th  or  10th  of 
the  month  was  first  shown,  however,  by  Quetelet, 
shortly  after  the  discovery  of  the  yearly  return  of 
the  November  phenomenon.  Since  that  time  an  ex 
traordinary  number  of  meteors  has  been  regularly 
observed,  both  in  Europe  and  America,  from  the 
7th  to  the  llth  of  the  month;  the  greatest  number 
being  generally  seen  on  the  10th.  In  1839,  Edward 
Heis,  of  Aix-la-Chapelle,  saw  160  meteors  in  one 
hour  on  the  night  of  the  10th.  In  1842,  he  saw  34 
in  ten  minutes  at  the  time  of  the  maximum.  In 
1861,  on  the  night  of  the  10th,  four  observers,  watch 
ing  together  at  New  Haven,  saw  in  three  hours — 
from  ten  to  one  o'clock — 289  meteors.  On  the  same 
night,  at  Natick,  Massachusetts,  two  observers  saw 
397  in  about  seven  hours.  At  London,  Mercer 
County,  Pennsylvania,  on  the  night  of  August  9th, 
1866,  Samuel  S.  Gilson,  Esq.,  watching  alone,  saw 
72  meteors  in  forty  minutes,  and,  with  an  assistant, 
(26) 


OTHER    METEORIC    RINGS.  27 

117  in  one  hour  and  fifteen  minutes.  Generally,  the 
number  observed  per  hour,  at  the  time  of  the  Au 
gust  maximum,  is  about  nine  times  as  great  as  on 
ordinary  nights.  Like  the  November  meteors,  they 
have  a  common  "radiant;"  that  is,  their  tracks, 
when  produced  backward,  meet,  or  nearly  meet,  in 
a  particular  point  in  the  constellation  Perseus. 

Of  the  315  meteoric  displays  given  in  Quetelet's 
"Catalogue  des  principales  apparitions  <Te*toiles  fi- 
lantes,"  63  seem  to  have  been  derived  from  the  Au 
gust  ring.  The  first  11  of  these,  with  one  exception, 
were  observed  in  China  during  the  last  days  of  July, 
as  follows: 

1 A.D.  811,  July  25th. 

o 820,  "  25th-30th. 

3 824,  "  26th-28th. 

4 830,  "  26th. 

5 -. 833,  "  27th. 

6 835,  "  20th. 

7 841,  "  25th-30th. 

8 924,  «  27th-30th. 

9 925,  "  27th-30th. 

10 926,  "  27th-30th. 

11 933,  "  25tk-30th. 

The  next  dates  are  1243,  August  2d,  and  1451, 
August  7th.  A  comparison  of  these  dates  indicates 
a  forward  motion  of  the  node  of  the  ring  along  the 
ecliptic.  This  was  pointed  out  several  years  since 
by  Boguslawski.  A  similar  motion  of  the  node  has 
also  been  found  in  the  case  of  the  November  ring. 
That  these  points  should  be  stationary  is,  indeed,  al 
together  improbable.  The  nodes  of  all  the  planetary 
orbits,  it  .is  well  known,  have  a  secular  variation. 
On  the  evening  of  August  10th,  1861,  at  about 


METEORIC    ASTRONOMY. 

llh.  30m.,  a  meteor  was  seen  by  Mr.  E.  C.  Herrick 
and  Prof.  A.  C.  Twining,  at  New  Haven,  Connecticut, 
which  "  was  much  more  splendid  than  Venus,  and  left 
a  train  of  sparks  which  remained  luminous  for  twenty 
seconds  after  the  meteor  disappeared."  The  same 
meteor  was  also  accurately  observed  at  Burlington, 
New  Jersey,  by  Mr.  Benjamin  Y.  Marsh.  It  was 
"conformable,"— that  is,  its  track  produced  back 
ward  passed  through  the  common  radiant — and  it 
was  undoubtedly  a  member  of  the  August  group. 
The  observations  were  discussed  by  Professor  H.  A. 
Newton,  of  Yale  College,  who  deduced  from  them 
the  following  approximate  elements  of  the  ring:* 

Semi-axis  major 0  84 

Eccentricity 0-28 

Perihelion  distance 0-60 

Inclination 'g4° 

Period  281  days. 

Motion,  retrograde. 

The  earth  moving  at  the  rate  of  68,000  miles  per 
hour,  is  at  least  five  days  in  passing  entirely  through 
the  ring.  This  gives  a  thickness  of  more  than 
8,000,000  miles. 

The  result  of  Professor  Newton's  researches  on 
the  oribit  of  this  ring,  though  undertaken  with  in 
adequate  data,  and  hence,  in  some  respects,  probably 
far  from  correct,  is  nevertheless  highly  interesting 
as  being  the  first  attempt  to  determine  the  orbit 
of  shooting-stars.  More  recent  investigations  have 
shown  a  remarkable  resemblance  between  the  ele 
ments  of  these  meteors  and  those  of  the  third  comet 

*  Silliman's  Journ.  for  Sept.  and  Nov.,  1861. 


OTHER    METEORIC    RINGS.  29 

of  1862.    The  former,  by  Schiaparelli,  and  the  latter, 
by  Oppolzer,  are  as  follows: 

Meteors  of  August  10th.  Comet  III.,  1862. 

Longitude  of  perihelion  343°  38'  344°  41 

Ascending  node 138    16  137    27 

Inclination 03      3  66    25 

Perihelion  distance 0-9643  0-9626 

Period 105  years  (?).  123  years  (?). 

Motion Retrograde.  Retrograde. 

This  similarity  is  too  great  to  be  accidental.  The 
August  meteors-  and  the  third  comet  of  1862  probably  be 
long  to  the  same  ring. 

III.  The  Meteors  of  April  18th-26th. 

The  following  dates  of  the  April  meteoric  showers 
are  extracted  from  Quetelet's  table  previously  re 
ferred  to : 


1  

A  D   401    April    9th. 

[8        AD 

1096    April  10th 

o 

538       "       7th 

9 

1122      "      llth 

3 

839       "     17th 

10 

1193      a      nth 

4  

997       it     i7th 

11 

1803,     "      20th 

5  

934       "     18th 

12 

1838      "      20th 

6 

1009,      "     16th. 

13... 

1841.     "      19th. 

1094,      «     10th.       14...  1850,     «      llth-17th. 


The  display  of  401  was.  witnessed  in  China,  and 
is  described  as  "very  remarkable."  That  of  1803 
was  best  observed  in  Virginia,  and  was  at  its  maxi 
mum  between  one  and  three  o'clock.  The  alarm  of 
fire  had  called  many  of  the  inhabitants  of  Richmond 
from  their  houses,  so  that  the  phenomenon  was  gen 
erally  witnessed.  The  meteors  "seemed  to  fall  from 
every  point  in  the  heavens,  in  such  numbers  as  to 

3* 


30  METEORIC    ASTRONOMY. 

resemble  a  shower  of  sky-rockets."  Some  were  of 
extraordinary  magnitude.  "One  in  particular,  ap 
peared  to  fall  from  the  zenith,  of  the  apparent  size  of 
a  ball  18  inches  in  diameter,  that  lighted  the  whole 
hemisphere  for  several  seconds." 

The  probability  that  the  meteoric  falls  about  the 
20th  of  April  are  derived  from  a  ring  which  inter 
sects  the  earth's  orbit,  was  first  suggested  by  Arago, 
in  1836.  The  preceding  list  indicates  a  forward 
motion  of  the  node.  The  radiant,  according  to  Mr. 

o 

G-reg,  is  about  Corona.  The  number  of  meteors 
observed  in  1838,  1841,  and  1850,  was  not  very  ex 
traordinary.  Recent  observations  indicate  April 
9th-12th  as  another  epoch.  The  radiant  is  in  Virgo. 

IV.  The  Meteors  of  December  6th-13th. 

On  the  13th  of  December,  1795,  a  large  meteoric 
stone  fell  in  England.  On  the  night,  between  the 
6th  and  7th  of  December,  1798,  Professor  Brandes, 
then  a  student  in  Gottingen,  saw  2000  shooting-stars. 
On  the  llth  of  the  month,  1836,  a  fall  of  meteoric 
stones,  described  by  Humboldt  as  "enormous,"  oc 
curred  near  the  village  of  Macao,  in  Brazil.  During 
the  last  few  years  unusual  numbers  of  shooting-stars, 
have  been  noticed  by  different  observers  from  the 
10th  to  the  13th;  the  maximum  occurring  about  the 
llth.  From  A.D.  848,  December  2d,  to  1847,  De 
cember  8th-10th,  we  find  14  star  showers  in  Quete- 
let's  catalogue,  derived,  probably,  from  this  meteoric 
stream.  As  in  other  cases,  the  dates  seem  to  show 
a  progressive  motion  of  the  node.  The  position  of 
the  radiant,  as  determined  by  Benjamin  V.  Marsh, 


OTHER    METEORIC    RINGS.  31 

Esq.,  of  Philadelphia,  from  observations  in  1861  and 
1862,  and  also  by  R.  P.  Greg,  Esq.,  of  Manchester, 
England,  is  at  a  point  midway  between  Castor  and 
Pollux. 

V.  The  Meteors  of  January  2d-3d. 

About  the  middle  of  the  present  century,  Mr. 
Julius  Schmidt,  of  Bonn,  a  distinguished  and  accu 
rate  observer,  designated  the  2d  of  January  as  a 
meteoric  epoch ;  characterizing  it, however,  as  "prob 
ably  somewhat  doubtful."  Recent  observations,  espe 
cially  those  of  R.  P.  Greg,  Esq.,  have  fully  confirmed 
it.  The  meteors  for  several  hours  are  said  to  be  as 
numerous  as  at  the  August  maximum.  The  radiant 
is  near  the  star  Beta  of  the  constellation  Bootes. 

Quetelet's  list  contains  at  least  five  exhibitions 
which  belong  to  this  epoch.  Two  or  three  others 
may  also  be  referred  to  it  with  more  or  less  proba 
bility. 


Several  other  meteoric  epochs  have  been  indicated ; 
some  of  which,  however,  must  yet  be  regarded  as 
doubtful.  In  thirty  years,  from  1809  to  1839, 12  falls 
of  bolides  and  meteoric  stones  occurred  from  the  27th 
to  the  29th  of  November.  Such  coincidences  can 
hardly  be  accidental.  Unusual  numbers  of  shooting- 
stars  have  also  been  seen  about  the  27th  of  July ;  from 
the  15th  to  the  19th  of  October,  and  about  the  middle 
of  February.  The  radiant,  for  the  last-mentioned 
epoch,  is  in  Leo  Minor.  The  numbers  observed  in 
October  are  said  to  be  at  present  increasing.  At  least 
seven  of  the  exhibitions  in  Quetelet's  catalogue  are 


32  METEORIC    ASTRONOMY. 

referable  to  this  epoch.      It  is  worthy  of  remark, 
moreover,  that  three  of  the  dates  specified  by  Mr. 
Greg  as  aerolite  epochs  are  coincident  with  those  of 
shooting-stars;  viz.,  February  15th-19th,  July  26th, 
and  December  13th.     The  whole  number  of  exhi 
bitions  enumerated  in  Quetelet's  catalogue  is  315. 
In  eighty-two  instances  the  day  of  the  month  on 
which  the  phenomenon  occurred  is  not  specified. 
Nearly  two-thirds  of  the  remainder,  as  we  have  seen, 
belong  to  established  epochs,  and  the  periodicity  of 
others  will  perhaps  yet  be  discovered.     But  reasons 
are  not  wanting  for  believing  that  our  system  is 
traversed    by  numerous   meteoric   streams   besides 
those   which   actually   intersect    the    earth's   orbit. 
The  asteroid  region  between  Mars  and  Jupiter  is 
probably  occupied  by  such  an  annulus.     The  num 
ber  of  these  asteroids  increases  as  their  magnitudes 
diminish;    and  this  doubtless  continues  to  be  the 
case  far  below  the  limit  of  telescopic  discovery.   The 
zodiacal  light  is  probably  a  dense  meteoric  ring,  or 
rather,  perhaps,  a  number  of  rings.     We  speak  "of  it 
as  dense  in  comparison  with  others,  which  are  invisi 
ble  except  by  the  ignition  of  their  particles  in  passing 
through  the  atmosphere.     From  a  discussion  of  the 
motions  of  the  perihelia  of  Mercury  and  Mars,  Le- 
verrier  has  inferred  the  existence  of  two  rings  of 
minute  asteroids;  one  within  the  orbit  of  Mercury, 
whose  mass  is  nearly  equal  to  that  of  Mercury  him 
self;  the  other  at  the  mean  distance  of  the  earth, 
whose  mass  cannot  exceed  the  tenth  part  of  the  mass 
of  the  earth. 

Within  the  last.few  years  a  distinguished  European 
savant,  Buys-Ballot,  of  Utrecht,  has   discovered  a 


OTHER    METEORIC    RINGS.  33 

short  period  of  variation  in  the  amount  of  s'olar  heat 
received  by  the  earth :  the  time  from  one  maximum  to 
another  exceeding  the  period  of  the  sun's  apparent 
rotation  by  about  twelve  hours.  The  variation  cannot 
therefore  be  due  to  any  inequality  in  the  heating 
power  of  the  different  portions  of  the  sun's  surface. 
The  discoverer  has  suggested  that  it  may  be  pro 
duced  by  a  meteoric  ring,  whose  period  slightly  ex 
ceeds  that  of  the  sun's  rotation.  Such  a  zone  might 
influence  our  temperature  by  partially  intercepting 
the  solar  heat. 

GENERAL  REMARKS. 

1.  The  average  number  of  shooting-stars  seen  in 
a  clear,  moonless  night  by  a  single  observer,  is  about 
8  per  hour.     One  observer,  however,  sees  only  about 
one-fourth  of  those  visible  from  his  point  of  observa 
tion.     About  30  per  hour  might  therefore  be  seen 
by  watching  the  entire  hemisphere.    In  other  words, 
720  shooting-stars  per  day  could  be  seen  by  the  naked 
eye  at  any  one  point  of  the  earth's  surface,  did  the 
sun,  moon,  and  clouds  permit. 

2.  The  mean  altitude  of  shooting-stars  above  the 
earth's  surface  is  about  60  miles. 

3.  The  number  visible  over  the  whole   earth  is 
about  10,460  times  the  number  to  be  seen  at  any  one 
point.     Hence  the  average  number  of  those  daily 
entering    the    atmosphere    and    having    sufficient 
magnitude  to  be  seen  by  the  naked  eye,  is  about 
7,532,600. 

4.  The  observations  of  Pape  and  Winnecke  indi 
cate  that  the  number  of  meteors  visible  through  the 
telescope,  employed  by  the  latter,  is  about  53  times 


34  METEORIC    ASTRONOMY. 

the  number  visible  to  the  naked  eye,  or  about 
400,000,000  per  day.*  This  is  two  per  day,  or  73,000 
per  century,  for  every  square  mile  of  the  earth's  sur 
face.  By  increasing  the  optical  power,  this  number 
would  probably  be  indefinitely  increased.  At  special 
times,  moreover,  such  as  the  epochs  of  the  great 
meteoric  showers,  the  addition  of  foreign  matter  to 
our  atmosphere  is  much  greater  than  ordinary.  It 
becomes,  therefore,  an  interesting  question  whether 
sensible  changes  may  not  thus  be  produced  in  the 
atmosphere  of  our  planet. 

5.  In  August,  1863,  20  shooting-stars  were  doubly 
observed  in  England;  that  is,  the}7  were  seen  at  two 
different  stations.     The  average  weight  of  these  me 
teors,  estimated — in  accordance  with  the  mechanical 
theory  of  heat — from  the  quantity  of  light  emitted, 
was  a  little  more  than  two  ounces. 

6.  A  meteoric  mass  exterior  to  the  atmosphere, 
and  consequently  non-luminous,  was  observed  on 
the  evening  of  October  4th,  1864,  by  Edward  Heis, 
a  distinguished  European  astronomer.   It  entered  the 
field  of  view  as  he  was  observing  the  milky  way,  and 
he  was  enabled  to  follow  it  over  11  or  12  decrees  of 

o 

its  path.  It  eclipsed,  while  in  view,  a  number  of  the 
fixed  stars. 


*  The  numerical  results  here  given  are  those  found  by  Professor 
Newton.     See  Silliinan's  Journ.  for  March,  1805. 


CHAPTER  III. 

AEROLITES. 

IT  is  now  well  known  that  much  greater  variety 
obtains  in  the  structure  of  the  solar  system  than  was 
formerly  supposed.  This  is  true,  not  only  in  regard 
to  the  magnitudes  and  densities  of  the  bodies  com 
posing  it,  but  also  in  respect  to  the  forms  of  their 
orbits.  The  whole  number  of  planets,  primary  and 
secondary,  known  to  the  immortal  author  of  the 
Mecanique  Celeste,  was  only  29.  This  number  has 
been  more  than  quadrupled  in  the  last  quarter  of  a 
century.  In  Laplace's  view,  moreover,  all  comets 
were  strangers  within  the  solar  domain,  having  en 
tered  it  from  without.  It  is  now  believed  that  a 
large  proportion  originated  in  the  system  and  belong 
properly  to  it. 

The  gradation  of  planetary  magnitudes,  omitting 
such  bodies  as  differ  but  little  from  those  given,  is 
presented  at  one  view  in  the  following  table: 

/  Name.  Diameter  in  miles. 

Jupiter 90,000 

Uranus 35,000 

The  Earth 7,926 

Mercury 3,000 

The  Moon 2,160 

Rhea,  Saturn's  5th  satellite 1,200 

Dione         "        4th        "       500 

(35) 


6b  METEORIC    ASTRONOMY. 

Name.  Diameter  \u  miles. 

Vesta* 260 

Juno 104 

Melpomene 52 

Polyhymnia 35 

Isis 25 

Atalanta 20 

Hestia 15 

The  diminution  doubtless  continues  indefinitely  be 
low  the  present  limit  of  optical  power.  If,  however, 
the  orbits  have  small  eccentricity,  such  asteroids 
could  not  become  known  to  us  unless  their  mean  dis 
tances  were  nearly  the  same  with  that  of  the  earth. 
But  from  the  following  table  it  will  be  seen  that  the 
variety  is  no  less  distinctly  marked  in  the  forms  of 
the  orbits: 

Name.  Eccentricity. 

Venus 0-00683 

The  Earth 0-01677 

Jupiter 0-04824 

Metis 0-12410 

Mercury 0-20562 

Pallas 0-24000 

Polyhymnia 0-33820 

Faye's  comet 0-55660 

D' Arrest's  "  0-66090 

Biela's        " 0-75580 

Encke's       "  0-84670 

Halley's      "  0-96740 

Fourth  comet  of  1857 /. 0-98140 

Fifth  comet  of  1858  (Donati's) 0-99620 

Third  comet  of  1827 0-99927 

Were  the  eccentricities  of  the  nearest  asteroids  equal 
to  that  of  Faye's  comet,  they  would  in  perihelion 

*  The  diameters  of  the  asteroids  are  derived  from  a  table  by  Prof. 
Lespiault,  in  the  Rep.  of  the  Smithsonian  Inst.  for  1861,  p.  216. 


AEROLITES.  37 

intersect  the  earth's  orbit.  Now,  in  the  case  of  both 
asteroids  and  comets,  the  smallest  are  the  most 
numerous;  and  as  this  doubtless  continues  below 
the  limit  of  telescopic  discovery,  the  earth  ought  to 
encounter  such  bodies  in  its  annual  motion.  It 
actually  does  so.  The  number  of  cometpids  thus  en 
countered  in  the  form  of  meteoric  stones,  fire-balls,  and 
shooting-stars  in  the  course  of  a  single  year  amounts 
to  many  millions.  The  extremely  minute,  and  such 
as  consist  of  matter  in  the  gaseous  form,  are  con 
sumed  or  dissipated  in  the  upper  regions  of  the  at 
mosphere.  ~No  deposit  from  ordinary  shooting-stars 
has  ever  been  known  to  reach  the  earth's  surface. 
But  there  is  probably  great  variety  in  the  physical 
constitution  of  the  bodies  encountered;  and  though 
comparatively  few  contain  a  sufficient  amount  of 
matter  in  the  solid  form  to  reach  the  surface  of  our 
planet,  scarcely  a  year  passes  without  the  fall  of 
meteoric  stones  in  some  part  of  the  earth,  either 
singly  or  in  clusters.  Now,  when  we  consider  how 
small  a  proportion  of  the  whole  number  are  proba 
bly  observed,  it  is  obvious  that  the  actual  occurrence 
of  the  phenomenon  can  be  by  no  means  rare.* 

Although  numerous  instances  of  the  fall  of  aero 
lites  had  been  recorded,  some  of  them  apparently 
well  authenticated,  the  occurrence  long  appeared  too 
marvelous  and  improbable  to  gain  credence  with 
scientific  men.  Such  a  shower  of  rocky  fragments 
occurred,  however,  on  the  26th  of  April,  1803,  at 

*  "It  appears  probable,  from  the  researches  of  Schreibevs,  that 
700  fall  annually." — Cosmos,  vol.  i.  p.  119  (Bohn's  Ed.).  Reichen- 
bach  makes  the  number  much  greater. 

4 


38  METEORIC    ASTRONOMY. 

L'Aigle,  in  France,  as  forever  to  dissipate  all  doubt 
on  the  subject.  At  one  o'clock  P.M.,  the  heavens 
being  almost  cloudless,  a  tremendous  noise,  like  that 
of  thunder,  was  heard,  and  at  the  same  time  an  im 
mense  fire-ball  was  seen  moving  with  great  rapidity 
through  the  atmosphere.  This  was  followed  by  a 
violent  explosion  which  lasted  several  minutes,  and 
which  was  heard  not  only  at  L'Aigle,  but  in  every 
direction  around  it  to  the  distance  of  seventy  miles. 
Immediately  after  a  great  number  of  meteoric  stones 
fell  to  the  earth,  generally  penetrating  to  some  dis 
tance  beneath  the  surface.  The  largest  of  these 
fragments  weighed  17J  pounds.  This  occurrence 
very  naturally  excited  great  attention.  M.  Biot, 
under  the  authority  of  the  government,  repaired  to 
L'Aigle,  collected  the  various  facts  in  regard  to  the 
phenomenon,  took  the  depositions  of  witnesses,  etc., 
and  finally  embraced  the  results  of  his  investigations 
in  an  elaborate  memoir. 

It  would  not  comport  with  the  design  of  the  pres 
ent  treatise  to  give  an  extended  list  of  these  phe 
nomena.  The  following  account,  however,  includes 
the  most  important  instances  of  the  fall  of  aerolites, 
and  also  of  the  displays  of  meteoric  fire-balls. 

1.  According  to  Livy  a  number  of  meteoric  stones 
fell  on  the  Alban  Hill,  near  Rome,  about  the  year 
654  B.C.     This  is  the  most  ancient  fall  of  aerolites 
on  record. 

2.  468  B.C.,  about  the  year  in  which  Socrates  was 
born.     A  mass  of  rock,  described  as  "  of  the  size  of 
two  millstones,"  fell  at  ^Egos  Potamos,  in  Thrace. 
An    attempt  to  rediscover  this  meteoric  mass,   so 
celebrated  in  antiquity,  was  recently  made,  but  with- 


AEROLITES.  39 

out  success.  Notwithstanding  this  failure,  Humboldt 
expressed  the  hope  that,  as  such  a  body  would  be  dif 
ficult  to  destroy,  it  may  yet  be  found,  "  since  the 
region  in  which  it  fell  is  now  become  so  easy  of 
access  to  European  travelers." 

3.  921  A.D.     An   immense  aerolite   fell   into   the 
river  (a  branch  of  the  Tiber)  at  Kami,  in  Italy.     It 
projected  three  or  four  feet  above  the  surface  of  the 
water. 

4.  1492,  November  7th.     An  aerolite,  weighing 
two  hundred  and  seventy-six  pounds,  fell  at  Ensis- 
heim,  in  Alsace,  penetrating  the  earth  to  the  depth 
of  three  feet.     This  stone,  or  the  greater  portion  of 
it,  may  still  be  seen  at  Ensisheim. 

5.  1511,  September  14th.    At  noon  an  almost  total 
darkening  of  the  heavens  occurred  at  Crema.    "Dur 
ing  this  midnight  gloom,"   says  a  writer  of  that 
period,  "  unheard-of  thunders,  mingled  with  awful 
lightnings,  resounded  through  the  heavens.    *    *    * 
On  the  plain  of  Crema,  where  never  before  was  seen 
a  stone  the  size  of  an  egg,  there  fell  pieces  of  rock 
of  enormous  dimensions  and  of  immense  weight,    It 
is  said  that  ten  of  these  were  found  weighing  a  hun 
dred  pounds  each."     A  monk  was  struck  dead  at 
Crema  by  one  of  these  rocky  fragments.     This  ter 
rific  meteoric  display  is  said  to  have  lasted  two  hours, 
and  1200  aerolites  were  subsequently  found. 

6.  1637,  November  29th.    A  stone,  weighing  fifty- 
four  pounds,  fell  on  Mount  Yaison,  in  Provence. 

7.  1650,  March  30th.     A  Franciscan  monk  was 
killed  at  Milan  by  the  fall  of  a  meteoric  stone. 

8.  1674.    Two  Swedish  sailors  were  killed  on  ship 
board  by  the  fall  of  an  aerolite. 


40  METEORIC    ASTRONOMY. 

9.  1686,  July  19th.      An   extraordinary  fire-ball 
was  seen  in  England;  its  motion  being  opposite  to 
that  of  the  earth  in  its  orbit.     Halley  pronounced 
this  meteor  a  cosmical  body.   (See  Philos.  Transact., 
vol.  xxix.) 

10.  1706,  June  7th.     A  stone  weighing  seventy- 
two  pounds  fell  at  Larissa,  in  Macedonia. 

11.  1719,  March  19th.    Another  great  meteor  was 
seen  in  England.     Its  explosion  occurred  at  an  ele 
vation  of  69  miles.      Notwithstanding   its   height, 
however,  the  report  was  like  that  of  a  broadside,  and 
so  great  was  the  concussion  that  windows  and  doors 
were  violently  shaken. 

12.  1751,  May  26th.     Two  meteoric  masses,  con 
sisting  almost  wholly  of  iron,  fell  near  Agram,  the 
capital  of   Croatia.      The   larger   fragment,  which 
weighs  seventy-two  pounds,  is  now  in  Vienna. 

13.  1756.   The  concussion  produced  by  a  meteoric 
explosion  threw  down  chimneys  at  Aix,  in  Provence, 
and  wras  mistaken  for  an  earthquake. 

14.  1771,  July  17th.      A  large  meteor  exploded 
near  Paris,  at  an  elevation  of  25  miles. 

15.  1783,  August  18th.     A  lire-ball  of  extraordi 
nary  magnitude  was  seen  in  Scotland,  England,  and 
France.     It  produced  a  rumbling  sound  like  distant 
thunder,  although  its  elevation  above   the  earth's 
surface  was  50  miles  at  the  time  of  its  explosion. 
The  velocity  of  its  motion  was  equal  to  that  of  the 
earth  in  its  orbit,  and  its  diameter,  according  to  Sir 
Charles  Blagden,  was  about  half  a  mile. 

16.  1790,  July  24th.   Between  nine  and  ten  o'clock 
at  night  a  very  large  igneous  meteor  was  seen  near 
Bourdeaux,  France.    Over  Barbotan  a  loud  explosion 


AEROLITES.  41 

was  heard,  which  was  followed  by  a  shower  of  mete 
oric  stones  of  various  magnitudes. 

17.  1794,  July.     A  fall  of  about  a  dozen  aerolites 
occurred  at  Sienna,  Tuscany. 

18.  1795,  December  13th.    A  large  meteoric  stone 
fell   near  Wold    Cottage,  in   Yorkshire,    England. 
The  following  account  of  the  phenomenon  is  taken 
from  Milner's  Gallery  of  Nature,  p.  134:   "  Several 
persons  heard  the  report  of  an  explosion  in  the  air, 
followed  by  a  hissing  sound;  and  afterward  felt  a 
shock,  as  if  a  heavy  body  had  fallen  to  the  ground 
at  a  little  distance  from  them.    One  of  these,  a  plow 
man,  saw  a  huge  stone  falling  toward  the  earth,  eight 
or  nine  yards  from  the  place  where  he  stood.  It  threw 
up  the  mould  on  every  side;  and  after  penetrating 
through  the  soil,  lodged  some  inches  deep  in  solid 
chalk  rock.    Upon  being  raised,  the  stone  was  found 
to  weigh  fifty-six  pounds.    It  fell  in  the  afternoon  of  a 
mild  but  hazy  day,  during  which  there  was  no  thun 
der  or  lightning;  and  the  noise  of  the  explosion  was 
heard  through  a  considerable  district." 

19.  1796,  February  19th.    A  stone  of  ten  pounds' 
weight  fell  in  Portugal. 

20.  1798,  March  12th.     A  stone  weighing  twenty 
pounds  fell  at  Sules,  near  Yille  Franche. 

21.  1798,  March  17th.    An  aerolite  weighing  about 
twenty  pounds  fell  at  Sale,  Department  of  the  Rhone. 

22.  1798,  December  19th.     A  shower  of  meteoric 
stones  fell  at  Benares,  in  the  East  Indies.    An  inter 
esting  account  of  the  phenomenon  was  given  by  J. 
Lloyd  Williams,  F.K.S.,  then  a  resident  in  Bengal. 
The  sky  had  been  perfectly  clear  for  several  days. 
At  eight  o'clock  in  the  evening  a  large  meteor  ap- 

4* 


42  METEORIC    ASTRONOMY. 

peared,  which  was  attended  with  a  loud  rumbling 
noise.  Immediately  after  the  explosion  a  sound  was 
heard  like  that  of  heavy  bodies  falling  in  the  neigh 
borhood.  Next  morning  the  fresh  earth  was  found 
turned  up  in  many  places,  and  aerolites  of  various 
sizes  were  discovered  beneath  the  surface. 

23.  1803,  April  26th.      The  shower  at  L'Aigle, 
previously  described. 

24.  1807,  December  14th.     A  large  meteor  ex 
ploded   over   Weston,    Connecticut.      The    height, 
direction,   velocity,   and   magnitude    of    this   body 
were  ably  discussed  by  Dr.  Bowditch  in  a  memoir 
communicated  to  the  American  Academy  of  Arts 
and    Sciences  in  1815.      The  following  condensed 
statement  of  the  principal  facts,  embodied  in  Dr. 
Bowditch's   paper,    is    extracted  from   the  People's 
Magazine  for  January  25th,  1834: 

"  The  meteor  of  1 807  was  observed  about  a  quarter- 
past  six  on  Monday  morning.  The  day  had  just 
dawned,  and  there  was  little  light  except  from  the 
moon,  which  was  just  setting.  It  seemed  to  be  half 
the  diameter  of  the  full  moon;  and  passed,  like  a 
globe  of  fire,  across  the  northern  margin  of  the  sky. 
It  passed  behind  some  clouds,  and  when  it  came  out 
it  flashed  like  heat  lightning.  It  had  a  train  of 
light,  and  appeared  like  a  burning  fire-brand  carried 
against  the  wind.  It  continued  in  sight  about  half  a 
minute,  and,  in  about  an  equal  space  after  it  faded, 
three  loud  and  distinct  reports,  like  those  of  a  four- 
pounder  near  at  hand,  were  heard.  Then  followed 
a  quick  succession  of  smaller  reports,  seeming  like 
what  soldiers  call  a  running  fire.  The  appearance 
of  the  meteor  was  as  if  it  took  three  successive  throes, 


AEROLITES.  43 

or  leaps,  and  at  each  explosion  a  rushing  of  stones 
was  heard  through  the  air,  some  of  which  struck  the 
ground  with  a  heavy  fall. 

"The  h'rst  fall  was  in  the  town  of  Huntington, 
near  the  house  of  Mr.  Merwin  Burr.  He  was  stand 
ing  in  the  road,  in  front  of  his  house,  when  the  stone 
fell,  and  struck  a  rock  of  granite  about  fifty  feet  from 
him,  with  a  loud  noise.  The  rock  was  stained  a 
dark-red  color,  and  the  stone  was  principally  shiv 
ered  into  very  small  fragments,  which  were  thrown 
around  to  a  distance  of  twenty  feet.  The  largest 
piece  was  about  the  size  of  a  goose  egg,  and  was  still 
warm. 

"The  stones  of  the  second  explosion  fell  about 
five  miles  distant,  near  Mr.  William  Prince's  resi 
dence,  in  Weston.  He  and  his  family  were  in  bed 
when  they  heard  the  explosion,  and  also  heard  a 
heavy  body  fall  to  the  earth.  They  afterward  found  a 
hole  in  the  earth,  about  twenty-five  feet  from  the 
house,  like  a  newly  dug  post-hole,  about  one  foot  in 
diameter,  and  two  feet  deep,  in  which  they  found  a 
meteoric  stone  buried,  which  weighed  thirty-five 
pounds.  Another  mass  fell  half  a  mile  distant,  upon 
a  rock,  which  it  split  in  two,  and  was  itself  shiv 
ered  to  pieces.  Another  piece,  weighing  thirteen 
pounds,  fell  a  half  a  mile  to  the  northeast,  into  a 
plowed  field. 

"At  the  last  explosion,  a  mass  of  stone  fell  in  a 
field  belonging  to  Mr.  Elijah  Seely,  about  thirty  rods 
from  the  house.  This  stone  falling  on  a  ledge,  was 
shivered  to  pieces.  It  plowed  up  a  large  portion  of 
the  ground,  and  scattered  the  earth  and  stones  to  the 
distance  of  fifty  or  a  hundred  feet.  Some  cattle  that 


44  METEORIC   ASTRONOMY. 

were  near  were  very  much  frightened,  and  jumped 
into  an  inclosure.  It  was  concluded  that  this  last 
stone,  before  being  broken,  must  have  weighed  about 
two  hundred  pounds.  These  stones  were  all  of  a 
similar  nature,  and  different  from  any  commonly 
found  on  this  globe.  When  first  found,  they  were 
easily  reduced  to  powder  by  the  fingers,  but  by  ex 
posure  to  the  air  they  gradually  hardened." 

25.  1859,  November  15th.    Between  nine  and  ten 
o'clock  in  the  morning,  an  extraordinary  meteor  was 
seen  in  several  of  the  New  England  States,  New 
York,  New  Jerse}r,  the  District  of  Columbia,  and 
Virginia.     The  apparent  diameter  of  the  head  was 
nearly  equal  to  that  of  the  sun,  and  it  had  a  train, 
notwithstanding  the  bright  sunshine,  several  degrees 
in  length.     Its  disappearance  on  the  coast  of  the 
Atlantic  was  followed  by  a  series  of  the  most  terrific 
explosions.     It  is  believed  to  have  descended  into 
the  water,  probably  into  Delaware  Bay.     A  highly 
interesting  account  of  this  meteor,  by  Prof.  Loomis, 
may  be  found  in  the  American  Journal  of  Science  and 
Arts  for  January,  1860. 

26.  1860,  May  1st.     About  twenty  minutes  before 
one  o'clock  P.M.,  a  shower  of  meteoric  stones — one 
of  the  most  extraordinary  on  record — fell  in  the  S. 
W.  corner  of  Guernsey  County,  Ohio.  Full  accounts 
of  the  phenomena  are  given  in  Sillimaris  Journal 
for  July,  1860,  and  January  and  July,  1861,  by  Pro 
fessors  E.  B.  Andrews,  E.  W.  Evans,  J.  L.  Smith, 
and  D.  W.  Johnson.    From  these  interesting  papers 
we  learn  that  the  course  of  the  meteor  was  about  40° 
west  of  north.     Its  visible  track  was  over  Wash 
ington  and  Noble  Counties,  and  the  prolongation  of 


AEROLITES.  45 

its  projection,  on  the  earth's  surface,  passes  directly 
through  New  Concord,  in  the  S.  E.  corner  of  Musk- 
ingum  County.  The  height  of  the  meteor,  when 
seen,  was  about  40  miles,  and  its  path  was  nearly 
parallel  with  the  earth's  surface.  The  sky,  at  the 
time,  was,  for  the  most  part,  covered  with  clouds 
over  northwestern  Ohio,  so  that  if  any  portion  of  the 
meteoric  mass  continued  on  its  course,  it  was  invisi 
ble.  The  velocity  of  the  meteor,  in  relation  to  the 
earth's  surface,  was  from  3  to  4  miles  per  second ;  and 
hence  its  absolute  velocity  in  the  solar  system  was 
from  20  to  21  miles  per  second.  This  would  indicate 
an  orbit  of  considerable  eccentricity. 

"At  'New  Concord,*  Muskingum  County,  where 
the  meteoric  stones  fell,  and  in  the  immediate  neigh 
borhood,  there  were  many  distinct  and  loud  reports 
heard.  At  New  Concord  there  were  first  heard  in 
the  sky,  a  little  southeast  of  the  zenith,  a  loud  deto 
nation,  which  was  compared  to  that  of  a  cannon  fired 
at  the  distance  of  half  a  mile.  After  an  interval  of 
ten  seconds  another  similar  report.  After  two  or 
three  seconds  another,  and  so  on  with  diminishing 
intervals.  Twenty-three  distinct  detonations  were 
heard,  after  which  the  sounds  became  blended  to 
gether  and  were  compared  to  the  rattling  fire  of  an 
awkward  squad  of  soldiers,  and  by  others  to  the 
roar  of  a  railway  train.  These  sounds,  with  their 
reverberations,  are  thought  to  have  continued  for 
two  minutes.  The  last  sounds  seemed  to  come  from 
a  point  in  the  southeast  45°  below  the  zenith.  The 


*  New  Concord  is  close  to  the  Guernsey  County  line.     Nearly  all 
the  stones  fell  in  Guernsey. 


46  METEORIC   ASTRONOMY. 

result  of  this  cannonading  was  the  falling  of  a  large 
number  of  stony  meteorites  upon  an  area  of  about 
ten  miles  long  by  three  wide.  The  sky  was  cloudy, 
but  some  of  the  stones  were  seen  first  as  'black 
specks/  then  as  'black  birds,'  and  finally  falling  to 
the  ground.  A  few  were  picked  up  within  twenty 
or  thirty  minutes.  The  warmest  was  no  warmer 
than  it  it  had  lain  on  the  ground  exposed  to  the  sun's 
rays.  They  penetrated  the  earth  from  two  to  three 
feet.  The  largest  stone,  which  weighed  one  hundred 
and  three  pounds,  struck  the  earth  at  the  foot  of  a 
large  oak  tree?  and,  after  cutting  off  two  roots,  one 
five  inches  in  diameter,  and  grazing  a  third  root,  it 
descended  two  feet  ten  inches  into  hard  clay.  This 
stone  was  found  resting  under  a  root  that  was  not 
cut  off.  This  would  seemingly  imply  that  it  entered 
the  earth  obliquely." 

Over  thirty  of  the  stones  which  fell  were  discovered, 
while  doubtless  many,  especially  of  the  smaller,  being 
deeply  buried  beneath  the  soil,  entirely  escaped  ob 
servation.  The  weight  of  the  largest  ten  was  four 
hundred  and  eighteen  pounds. 

27.  1864,  May  14th.  Early  in  the  evening  a  very 
large  and  brilliant  meteor  was  seen  in  France,  from 
Paris  to  the  Spanish  border.  At  Montauban,  and 
in  the  vicinity,  loud  explosions  were  heard,  and 
showers  of  meteoric  stones  fell  near  the  villages  of 
Orgueil  and  Nohic.  The  principal  facts  in  regard  to 
this  meteor  are  the  following: 

Elevation  when  first  seen,  over 55  miles. 

"          at  the  time  of  its  explosion 20     " 

Inclination  of  its  path  to  the  horizon 20° or 25° 

Velocity  per  second,  about 20  miles, 


AEROLITES.  47 

or  equal  to  that  of  the  earth's  orbital  motion.  "  This 
example,"  says  Prof.  Newton,  "affords  the  strongest 
proof  that  the  detonating  and  stone-producing  me 
teors  are  phenomena  not  essentially  unlike." 

The  foregoing  list  contains  but  a  small  proportion 
even  of  those  meteoric  stones  the  date  of  whose  fall 
is  known.  But  besides  these,  other  masses  have 
been  found  so  closely  similar  in  structure  to  aerolites 
whose  descent  has  been  observed,  as  to  leave  no 
doubt  in  regard  to  their  origin.  One  of  these  is  a 
mass  of  iron  and  nickel,  weighing  sixteen  hundred 
and  eighty  pounds,  found  by  the  traveler  Pallas,  in 
1749,  at  Abakansk,  in  Siberia.  This  immense  aero 
lite  may  be  seen  in  the  Imperial  Museum  at  St. 
Petersburg.  On  the  plain  of  Otumpa,  in  Buenos 
Ayres,  is  a  meteoric  mass  7J-  feet  in  length,  partly 
buried  in  the  ground.  Its  estimated  weight  is  thirty- 
three  thousand  six  hundred  pounds.  A  specimen  of 
this  stone,  weighing  fourteen  hundred  pounds,  has 
been  removed  and  deposited  in  one  of  the  rooms  of 
the  British  Museum.  A  similar  block,  of  meteoric 
origin,  weighing  twelve  or  thirteen  thousand  pounds, 
was  discovered  some  years  since  in  the  Province  of 
Bahia,  in  Brazil. 

Some  of  the  inferences  derived  from  the  examin 
ation  of  meteoric  stones,  and  the  consideration  of 
the  phenomena  attending  their  fall,  are  the  follow 
ing  : 

1.  K.  P.  Greg,  Esq.,  of  Manchester,  England,  who 
has  made  luminous  meteors  a  special  study,  has 
found  that  meteoric  stone-falls  occur  with  greater 
frequency  than  usual  on  or  about  particular  days.  He 
calls  attention  especially  to  five  aerolite  epochs,  viz.: 


48  METEORIC   ASTRONOMY. 

February  15th-19th;  May  19th;  July  26th;  Novem 
ber  29th,  and  December  13th. 

2.  It  is  worthy  of  remark  that  no  new  elements 
have  been  found  in  meteoric  stones.     Humboldt,  in 
his  Cosmos,  called  attention  to  this  interesting  fact. 
"I  would  ask,"  he  remarks,  "why  the  elementary 
substances    that   compose    one    group    of   cosmical 
bodies,  or  one  planetary  system,  may  not  in  a  great 
measure  be  identical?     Why  should  we  not  adopt 
this  view,  since  we  may  conjecture  that  these  plan 
etary  bodies,  like  all  the  larger  or  smaller  agglomer 
ated  masses  revolving  round  the   sun,   have  been 
thrown  off  from  the  once  far  more  expanded  solar 
atmosphere,  and  have  been  formed  from  vaporous 
rings    describing    their    orbits    round    the    central 
body?"* 

3.  But  while  aerolites  contain  no  elements  but 
such  as  are  found  in  the  earth's  crust,  the  manner  in 
which  these  elements  are  combined  and  arranged  is 
so  peculiar  that  a  skillful  mineralogist  will  readily 
distinguish  them  from  terrestrial  substances. 

4.  Of  the  eighteen  or  nineteen  elements  hitherto 
observed  in  meteoric  stones,  iron  is  found  in  the 
greatest  abundance.    The  specific  gravities  vary  from 
1-94  to  7-901:  the  former  being  that  of  the  stone  of 
Alais,  the  latter,  that  of  the   meteorite  of  Wayne 
County,  Ohio,  described  by  Professor  J.  L.  Smith  in 
Sillimarts  Journal  for  November,  1864,  p.  385.     In 
most  cases,  however,  the  specific  gravity  is  about  3 
or  4. 

5.  The  contemplation  of  the  heavenly  bodies  has 

*  Cosmos,  vol.  i.  p.  120. 


AEROLITES.  49 

often  produced  in  thoughtful  minds  an  intense  desire 
to  know  something  of  their  nature  and  physical  con 
stitution.  This  curiosity  is  gratified  in  the  examin 
ation  of  aerolites.  To  handle,  weigh,  inspect,  and 
analyze  bodies  that  have  \vandered  unnumbered 
ages  through  the  planetary  spaces  —  perhaps  ap 
proaching  in  their  perihelia  within  a  comparatively 
short  distance  of  the  solar  surface,  and  again  reced 
ing  in  their  aphelia  to  the  limits  of  the  planetary 
system — must  naturally  excite  a  train  of  pleasurable 
emotions. 

6.  It  is  highly  probable  that  in  pre-historic  times, 
before  the  solar  system  had  reached  its  present  stags 
of  maturity,  those  chaotic  wanderers  were  more  nu 
merous  in  the  vicinity  of  the  earth's  orbit  than  in  re 
cent  epochs.  Even  now  the  interior  planets,  Mercury 
and  Venus,  appear  to  be  moving  through  the  masses 
of  matter  which  constitute  the  zodiacal  light.     It 
would  seem  probable,  therefore,  that  they  are  re 
ceiving  from  this  source  much  greater  accretions  of 
matter  than  the  earth. 

7.  As  Mercury's  orbit  is  very  eccentric,  he  is  be 
yond  his  mean  distance  during  much  more  than  half 
his  period.    Hence,  probably,  the  greater  increments 
of  meteoric  matter  are  derived  from  such  portions  of 
the  zodiacal  light  as  have  a  longer  period  than  Mer 
cury  himself.     If  so,  the  tendency  would  be  to  di 
minish  slowly  the  planet's  mean  motion.     Such  a 
lengthening  of  the  period  has  been   actually  dis 
covered.* 


*  Leverrier's  Annals  of  the  Observ 


CHAPTER    IV. 

CONJECTURES    IN    REGARD    TO    METEORIC    EPOCHS. 

IT  is  highly  probable  that  aerolites  and  shooting- 
stars  are  derived  either  from  rings  thrown  off  in  the 
planes  of  the  solar  or  planetary  equators,  or  from 
streams  of  nebulous  matter  drawn  into  the  solar 
system  by  the  sun's  attraction.  Such  annuli  or 
streams  would  probably  each  furnish  an  immense 
number  of  meteor-asteroids.  If  any  rings  intersect 
the  earth's  orbit,  our  planet  must  encounter  such 
masses  as  happen  at  the  same  time  to  be  passing  the 
point  of  intersection.  This  must  be  repeated  at  the 
same  epoch  in  different  years;  the  frequency  of  the 
encounter  of  course  depending  on  the  closeness  and 
regularity  with  which  the  masses  are  distributed 
around  the  ring.  Accordingly  it  has  been  found 
that  not  only  the  meteors  of  November  14th  and  of 
the  epochs  named  in  Chapter  II.  have  their  respective 
radiants,  but  also  those  of  many  other  nights.  Mr. 
Alexander  S.  Herschel,  of  Collins-wood,  England, 

O  O 

states  that  fifty-six  such  points  of  divergence  are  now 
well  established.  We  have  mentioned  in  a  previous 
chapter  that  Mr.  Greg,  of  Manchester,  has  specified 
several  epochs  at  which  fire-balls  appear,  and  meteoric 
stone-falls  occur,  with  unusual  frequency.  The  num 
ber  of  £hese  periods  will  probably  be  increased  by 
future  observations.  Perhaps  the  following  facts 
(50) 


CONJECTURES    IN    REGARD    TO    METEORIC    EPOCHS.       51 

may  justify  the  designation  of  July  13th-14th  as 
such  an  epoch : 

1.  On  the  13th  of  July,   1797,  a  large  fire-ball 
was  seen  in  Gb'ttingen. 

2.  On  the  14th  of  July,  1801,  a  fire-ball  was  seen 
in  Montgaillard. 

3.  On  the  14th  of  July,  1845,  a  brilliant  meteor 
was  seen  in  London. 

4.  On  the  13th  of  July,  1846,  at  about  9h.  and 
30m.  P.M.,  a  brilliant  fire-ball  passed  over  Maryland 
and  Pennsylvania,  and  was  seen  also  in  Virginia, 
Delaware,  New  Jersey,  New  York,  and  Connecticut. 
Its  course  was  north,  about  thirty  degrees  east,  and 
the  projection  of  its  path  on  the  earth's  surface  passed 
about  four  miles  west  of  Lancaster,  Pennsylvania, 
and  nearly  through  Mauch  Chunk,  in  Carbon  County. 
When  west  of  Philadelphia  its  angle  of  elevation,  as 
seen  from  that  city,  was  forty-two  degrees.     Conse 
quently  its  altitude,  when  near  Lancaster,  was  about 
fifty-nine  miles.     The  projection  of  its  visible  path, 
on  the  earth's  surface,  was  at  least  two  hundred  and 
fifty  miles  in  length.     Its  height,  when  nearest  Get 
tysburg,  was  about  seventy  miles,  and  it  disappeared 
at  an  elevation  of  about  eighteen  miles,  near  the 
south  corner  of  Wayne  County,  Pennsylvania.     Its 
apparent  diameter,  as  seen  from  York  and  Lancaster, 
was  about  half  that  of  the  moon,  and  its  estimated 
heliocentric  velocity  was  between  twenty  and  twenty- 
five  miles. 

The  author  was  assured  by  persons  in  Harford 
County,  Maryland,  and  also  in  York,  Pennsylvania, 
that  shortly  after  the  disappearance  of  the  meteor  a 
distinct  report,  like  that  of  a  distant  cannon,  was 


52  METEORIC    ASTRONOMY. 

heard.  As  might  be  expected,  their  estimates  of  the 
interval  which  elapsed  were  different;  but  Daniel  M. 
Ettinger,  Esq.,  of  York,  who  was  paying  particular 
attention,  in  expectation  of  a  report,  stated  that  it 
was  a  little  over  six  minutes.  This  would  indicate 
a  distance  of  about  seventy-five  miles.  The  sound 
could  not  therefore  have  resulted  from  an  explosion 
at  or  near  the  termination  of  the  meteor's  observed 
path.  The  inclination  of  the  meteoric  track  to  the 
surface  of  the  earth  was  such  that  the  body  could 
not  have  passed  out  of  the  atmosphere.  As  no  aero 
lites,  however,  were  found  beneath  any  part  of  its 
path,  perhaps  the  entire  mass  may  have  been  dissi 
pated  before  reaching  the  earth. — SUlimaris  Journal 
for  May,  1866. 

5.  On  the  14th  of  July,  1847,  a  remarkable  fall 
of  aerolites  was  witnessed  at  Braunau,  in  Bohemia. 
Humboldt  states  that  "the  fallen  masses  of  stone 
were  so  hot,  that,  after  six  hours,  they  could  not  be 
touched  without  causing  a  burn."  An  analysis  of 
some  of  the  fragments,  by  Fischer  and  Duflos,  gave 
the  following  result: 

Iron 91-862 

Nickel 5-517 

Cobalt 0-529 

Copper,  manganese,  arsenic,  calcium,  magne 
sium,  silicium,  carbon,  chlorine  and  sulphur.     2-072 


100-000 


6.  On  the  13th  of  July,  1848,  a  brilliant  fire-ball 
was  seen  at  Stone-Easton,  Somerset,  England. 

7.  On  the  13th  of  July,  1852,  a  large  bolide  was 
seen  in  London. 


CONJECTURES    IN    REGARD    TO    METEORIC    EPOCHS.       53 

8.  On  the  14th  of  July,  1854,  a  fire-ball  was  seen 
at  Senftenberg. 

9.  On  the   13th  of  July,   1855,   ti  meteor,  three 
times  as  large  as  Jupiter,  was  seen  at  Nottingham, 
England. 

10.  "One  of  the  most  celebrated  falls  that  have 
occurred  of  late  years  is  that  which  happened  on  the 
14th  of  July,  1860,  between  two  and  half-past  two  in 
the  afternoon,  at  Dhurmsala,  in  India.    The  aerolite 
in  question  fell  with  a  most  fearful  noise,  arid  terri 
fied  the  inhabitants  of  the  district  not  a  little.    Several 
fragments  were  picked  up  by  the  natives,  and  carried 
religiously  away,  with  the  impression  that  they  had 
been  thrown  from  the  summit  of  the  Himalayas  by 
an  invisible  Divinity.    Lord  Canning  forwarded  some 
of  these  stones  to  the  British  Museum  and  to  the  Vi 
enna  Museum.    Mr.  J.  R.  Saunders  also  sent  some  of 
the  stones  to  Europe.     It  appears  that,  soon  after 
their  fall,  the  stones  were  intensely  cold.*     They  are 
ordinary  earthy  aerolites,  having  a  specific  gravity 
of  3-151,  containing  fragments  of  iron  and  iron  py- 


*  "  This  is  a  remarkable  example  of  a  stone  arriving  on  the  earth 
with  a  temperature  approaching  that  of  the  interplanetary  spaces. 
Aerolites  containing  much  iron,  a  substance  which  conducts  heat 
well,  get  thoroughly  heated  by  their  passage  through  the  atmos 
phere.  But  the  stony  aerolites,  containing  less  iron,  conducting 
heat  badly,  preserve  in  their  interior  the  temperature  of  the  locality 
from  which  they  fall;  their  surface  only  is  heated,  and  generally 
fused.  When  the  stones  are  large,  the  excessive  cold  of  their  interior 
portion,  which  must  be  nearly  that  of  interplanetary  space,  is  re 
marked;  but  when  small,  they  remain  hot  for  some  time." — Dr. 
P  hips  on. 

5* 


54  METEORIC   ASTRONOMY. 

rites;  they  have  an  uneven  texture,  and  a  pale-gray 
color." 

11.  At  a  quarter-past  ten  o'clock  on  the  evening 
of  July  13th,  1864,  a  large  fire-ball  was  seen  in  New 
England.*     The  hour  of  its  appearance,  it  will  be 
observed,  was  nearly  the  same  with  that  of  the  bo 
lide  of  July  13th,  1846;   and  it  is  also  worthy  of 
remark  that  their  directions  were  nearly  the  same. 
The  meteor  of  1864  had  a  tail  three  or  four  degrees 
in  length,  and  the  body,  like  that  of  1846,  exploded 
with  a  loud  report. 

12.  On  the  8th  of  July,  1186,  an  aerolite  fell  at 
Mons,  in  Belgium  (Quetelet's  Physique  du  Globe,  p. 
320).    A  forward  motion  of  the  node,  somewhat  less 
than  that  observed  in  the  rings  of  November  and 
August,  would  give  a  correspondence  of  dates  be 
tween  the  falls  of  1186,  1847,  and  1860. 

With  the  exception  of  the  last,  which  is  doubtful, 
these  phenomena  all  occurred  within  a  period  of 
67  years. 

THE  EPOCH  OF  NOVEMBER  29. 

It  has  been  stated  that  in  different  years  meteoric 
stones  have  fallen  about  the  29th  of  November.  One 
of  the  most  recent  aerolites  which  can  be  assigned 
to  this  epoch  is  that  which  fell  on  the  30th  of  No 
vember,  1850,  at  Shalka,  in  Bengal.  It  may  be 
mentioned,  as  at  least  a  coincidence,  that  the  earth 
passes  the  approximate  intersection  of  her  orbit  with 
that  of  Biela's  comet  at  the  date  of  this  epoch.  Do 

*  Silliman's  Journal,  September,  1804. 


CONJECTURES    IN   REGARD   TO   METEORIC    EPOCHS.       55 

other  bodies  besides  the  two  Biela  comets  move  in 
the  same  ellipse?  It  is  worthy  of  remark  that  two 
star  showers  have  been  observed  at  this  date:  one 
in  China,  A.D.  930,  the  other  in  Europe,  1850  (see 
Quetelet's  Catalogue).  It  is  certainly  important 
that  the  meteors  of  this  epoch  should  be  carefully 
studied. 


CHAPTER  Y. 

GEOGRAPHICAL  DISTRIBUTION  OF  METEORIC  STONES — 
DO  AEROLITIC  FALLS  OCCUR  MORE  FREQUENTLY  BY 
DAY  THAN  BY  NIGHT?  —  DO  METEORITES,  BOLIDES, 
AND  THE  MATTER  OF  ORDINARY  SHOOTING-STARS, 
COEXIST  IN  THE  SAME  RINGS  ? 

PROFESSOR  CHARLES  UPHAM  SHEPARD,  of  Amherst 
College,  who  has  devoted  special  attention  to  the 
study  of  meteoric  stones,  has  designated  two  districts 
of  country,  one  in  each  continent,  but  both  in  the 
northern  hemisphere,  in  which  more  than  nine-tenths 
of  all  known  aerolites  have  fallen.  He  remarks: 
"The  fall  of  aerolites  is  confined  principally  to  two 
zones;  the  one  belonging  to  America  is  between  33° 
and  44°  north  latitude,  and  is  about  25°  in  length. 
Its  direction  is  more  or  less  from  northeast  to  south 
west,  following  the  general  line  of  the  Atlantic  coast. 
Of  all  known  occurrences  of  this  phenomenon  dur 
ing  the  last  fifty  years,  92-8  per  cent,  have  taken 
place  within  these  limits,  and  mostly  in  the  neigh 
borhood  of  the  sea.  The  zone  of  the  Eastern  continent 
—  with  the  exception  that  it  extends  ten  degrees 
more  to  the  north — lies  between  the  same  degrees 
of  latitude,  and  follows  a  similar  northeast  direction, 
but  is  more  than  twice  the  length  of  the  American 
zone.  Of  all  the  observed  falls  of  aerolites,  90-9  per 
cent,  have  taken  place  within  this  area,  and  were  also 
(56) 


DISTRIBUTION    OF    METEORIC    STONES.  57 

concentrated  in  that  half  of  the  zone  which  extends 
along  the  Atlantic." 

The  facts  as  stated  by  Professor  Shepard  are,  of 
course, unquestionable.  It  seems,  however,  extremely 
improbable  that  the  districts  specified  should  receive 
a  much  larger  proportion  of  aerolites  than  others  of 
equal  extent.  How,  then,  are  the  facts  to  be  ac 
counted  for?  We  answer,  the  number  of  aerolites 
seen  to  fall  in  a  country  depends  upon  the  number  of 
its  inhabitants.  The  ocean,  deserts,  and  uninhabited 
portions  of  the  earth's  surface  afford  no  instances  of 
such  phenomena,  simply  for  the  want  of  observers. 
In  sparsely  settled  countries  the  fall  of  aerolites 
would  not  unfrequently  escape  observation;  and  as 
such  bodies  generally  penetrate  the  earth  to  some 
depth,  the  chances  of  discovery,  when  the  fall  is  not 
observed,  must  be  exceedingly  rare.  'Now  the  part 
of  the  American  continent  designated  by  Professor 
Shepard,  it  will  be  noticed,  is  the  oldest  and  most 
thickly  settled  part  of  the  United  States;  while  that 
of  the  Eastern  continent  stretches  in  like  manner 
across  the  most  densely  populated  countries  of  Eu 
rope.  This  fact  alone,  in  all  probability,  affords  a 
sufficient  explanation  of  Prof.  Shepard's  statement.* 

Do  aerolites  fall  more  frequently  by  day  than  by  night? 
— Mr.  Alexander  S.  Herschel,  of  Collingwood,  Eng 
land,  has  with  much  care  and  industry  collected  and 
collated  the  known  facts  in  regard  to  bolides  and 
aerolites.  One  result  of  his  investigations  is  that  a 
much  greater  number  of  meteoric  stones  are  ob- 


*  The  same  explanation  is  given  by  T.  M.  Hall,   F.G.S.,  in  the 
Popular  Science  Review  for  Oct.  1866. 


58  METEORIC   ASTRONOMY. 

served  to  fall  by  day  than  by  night.  From  this  he 
infers  that,  for  the  most  part,  the  orbits  in  which 
they  move  are  interior  to  that  of  the  earth.  The  fact, 
however,  is  obviously  susceptible  of  a  very  different 
explanation — an  explanation  quite  similar  to  that  of 
the  frequent  falls  in  particular  districts.  At  night  the 
number  of  observers  is  incomparably  less  ;  and  hence  many 
aerolites  escape  detection.  There  would  seem  to  be  no 
cause,  reason,  or  antecedent  probability  of  these  falls 
being  more  frequent  at  one  hour  than  another  in  the 
whole  twenty-four. 

The  coexistence  of  meteorites,  bolides,  and  the  matter  of 
shooting-stars  in  the  same  rings? — It  has  been  stated 
on  a  previous  page  that  several  aerolite  epochs  are 
coincident  with  those  of  shooting-stars.  Is  the 
number  of  such  cases  sufficient  to  justify  the  con 
clusion  that  the  correspondence  of  dates  is  not  acci 
dental?  We  will  consider, 

I.  The  Epoch  of  November  llth-14th. 

1.  1548,  November  6th.    A  very  large  detonating 
meteor  was  seen  at  Mansfield,  Thuringia,  at  two 
o'clock  in  the  morning.     The  known  rate  of  move 
ment  of  the  node  brings  this  meteor  within  the  No 
vember  epoch. 

2.  1624,  November  7th.    A  large  fire-ball  was  seen 
at  Tubingen.     The  motion  of  the  node  brings  this 
also  within  the  epoch. 

3.  1765,  November  llth.    A  bright  meteoric  light 
was  observed  at  Frankfort. 

4.  1791,  November  llth.     A  large  meteor  was 
seen  at  Gottingen  and  Lilienthal. 


DISTRIBUTION    OF    METEORIC    STONES.  59 

5.  1803,  November  13th.    A  fire-ball,  twenty-three 
miles  high,  was  seen  at  London  and  Edinburgh. 

6.  1803,  November  13th.    A  splendid  meteor  was 
seen  at  Dover  and  Harts. 

7.  1808,  November  llth.     A  fire-ball  was  seen  in 
England. 

8.  1818,  November  13th.     A  fire-ball  was  seen  at 
Gosport. 

9.  1819,  November  13th.     A  fire-ball  was  seen  at 
St.  Domingo. 

10.  1820,  November   12th.     A  large  detonating 
meteor  was  seen  at  Cholirnschk,  Russia. 

11.  1822,  November  12th.     A  fire-ball  appeared 
at  Potsdam. 

12.  1828,  November  12th.     A  meteor  \vas  seen  in 
full  sunshine  at  Sury,  Erance. 

13.  1831,  November  13th.    A  fire-ball  was  seen  at 
Bruneck. 

14.  1831,  November  13th.    A  brilliant  meteor  was 
seen  in  the  North  of  Spain. 

15.  1833,  November  12th.     A  fire-ball  was  seen 
in  Germany. 

16.  1833,  November  13th.     A  meteor,  two-thirds 
the  size  of  the  moon,  was  seen  during  the  great  me 
teoric  shower  in  the  United  States. 

17.  1834,  November  13th.     A  large  fire-bail  was 
seen  in  North  America. 

18.  1835,  November  13th.     Several  aerolites  fell 
near  Belmont,  Department  de  1'Ain,  France. 

19.  1836,  November  llth.      An  aerolitic  fall  oc 
curred  at  Macao,  Brazil. 

20.  1837,  November  12th.    A  remarkable  fire-ball 
was  seen  in  England. 


60  METEORIC   ASTRONOMY. 

21.  1838,  November  13th.     A  large  fire-ball  was 
seen  at  Cherbourg. 

22.  1849,  November  13th.     An  extraordinary  me 
teor  appeared  in  Italy.     "Seen  in  the  southern  sky. 
Varied  in  color;    a  bright  cloud  visible  one  and  a 
half  hour  after;    according  to  some  a  detonation 
heard  fifteen  minutes  after  bursting.    Seen  also  like 
a  stream  of  fire  between  Tunis  and  Tripolis,  where 
a  shower  of  stones  fell;  some  of  them  into  the  town 
of  Tripolis  itself." 

23.  1849,  November  13th.     A  large  meteor  was 
seen  at  Mecklenburg  and  Breslau. 

24.  1856,  November  12th.     A  meteoric  stone  fell 
at  Trenzano,  Italy. 

25.  1866,  November  14th.     At  Athens,  Greece,  a 
large  number  of  bolides  was  seen  by  Mr.  J.  F.  Julius 
Schmidt,  during  the  shower  of  shooting-stars.     One 
of  these  fire-balls  was  of  the  first  class,  and  left  a 
train  which  was  .visible  one  hour  to  the  naked  eye. 

II.  The  Epoch  of  August  7th-llth. 

1.  1642,  August  4th.     A  meteoric  stone  fell  in 
Suffolk  County,  England. 

2.  1650,  August  6th.    An  aerolite  fell  in  Holland. 
The  observed  motion  of  the  node  brings  both  these 
stone-falls  within  the  epoch. 

3.  1765,  August  9th.     A  large  bolide  was  seen  at 
Greenwich. 

4.  1773,  August   8th.     A   fire-ball   was   seen    at 
Northallerton. 

5.  1800,  August  8th.    A  large  meteor  was  seen  in 
different  parts  of  North  America. 


DISTRIBUTION    OF    METEORIC    STONES.  61 

6.  1802,  August  10th.      A  fire-ball  appeared  at 
Quedlinburg. 

7.  1807,  August  -9th.     A  bolide  was  seen  at  Nu- 
renberg. 

8.  1810,  August  10th.     A  stone  weighing  seven 
and  three-quarter  pounds  fell  at  Tipperary,  Ireland. 

9.  1816,  August  7th.   In  Hungary  a  large  fire-ball 
was  seen  to  burst,  with  detonations. 

10.  1817,  August  7th.     A  brilliant  fire-ball  was 
seen  at  Augsburg. 

11.  1818,  August  10th.    A  meteoric  stone,  weigh 
ing  seven  pounds,  fell  at  Slobodka,  Russia. 

12.  1822,  August  7th.     A  meteorite  fell  at  Ka- 
donah,  Agra. 

13.  1822,  August  7th.     A  large  meteor  was  seen 
in  Moravia. 

14.  1822,  August  llth.    "A  large  mass  of  fire  fell 
down  with  a  great  explosion"  near  Coblentz. 

15.  1823,  August  7th.     Two  meteoric  stones  fell 
in  Nobleboro',  Maine. 

16.  1826,  August  8th.      A  fire-ball  was  seen  at 
Odensee. 

17.  1826,  August  llth.    A  bright  meteor  appeared 
at  Halle. 

18.  1833,  August  10th,     A  fire-ball  was  seen  at 
Worcestershire,  England. 

19.  1834,  August   10th.     A  bolide   appeared   at 
Brussels. 

20.  1838,  August  9th.    A  fine  meteor  was  seen  in 
Germany. 

21.  1839,  August  7th.     A  splendid  fire-ball  was 
seen  at  sea. 

6 


62  METEORIC    ASTRONOMY. 

22.  1840,    August   7th.      A   bolide   appeared   at 
Naples. 

23.  1841,  August  10th.     An  aerolite  fell  at  Iwan, 
Hungary. 

24.  1842,  August  9th.     A  greenish  fire-ball  was 
seen  at  Hamburg. 

25.  1844,  August  8th.     A  large  meteor  was  seen 
in  Brittany. 

26.  1844,  August  10th.     A  fire-ball  was  seen  at 
Hamburg. 

27.  1845,  August  10th.     A  brilliant  meteor  was 
seen  at  London  and  Oxford. 

28.  1847,  August  9th.     A  large  irregular  meteor, 
"like  a  bright  cloud  of  smoke,"  was  seen  at  Brussels. 

29.  1850,  August  10th.     A  meteor  as  large  as  the 
moon  was  seen  in  Ireland. 

30.  1850,  August  10th.     A  very  large  bolide  was 
observed  in  Paris. 

31.  1850,  August  llth.     A  fire-ball  was  seen  in 
Paris. 

32.  1853,  August  7th.     A  bolide  was  observed  at 
Glasgow. 

33.  1853,  August  7th.     A  meteor  twice  as  large 
as  Venus  was  seen  at  Paris. 

34.  1853,  August  9th.     A  large  meteor  was  seen 
to  separate  into  two  parts. 

35.  1855,  August  10th.      A  bluish  meteor,  five 
times  as  large  as  Jupiter,  was  seen  at  Nottingham. 

36.  1857,  August  llth.     A  bolide  was  seen  in 
Paris. 

37.  1859,  August  7th.     A  detonating  meteor  ap 
peared  in  Germany. 


DISTRIBUTION    OF    METEORIC    STONES.  63 

38.  1859,  August  llth.   A  meteoric  stone  fell  near 
Albany,  New  York. 

39.  1859,  August  llth.     A  fine  meteor  was  seen 
at  Athens. 

40.  1862,  August  8th.     A  meteoric  stone-fall  oc 
curred  at  Pillistfer,  Russia. 

41.  1863,  August  llth.   An  aerolite  fell  at  Shytal, 
India. 

III.  The  Epoch  of  December  6th-13th. 

The  following  falls  of  meteoric  stones  have  occured 
at  this  epoch : 

1.  1795,  December  13th.    At  Wold  Cottage,  Eng 
land. 

2.  1798,  December  13th.    At  Benares,  India. 

3.  1803,  December  13th.  At  Massing,  Bavaria. 

4.  1813,  December  13th.  At  Luotolaks,  Finland. 

5.  1858,  December  9th.     At  Ausson,  France. 

6.  1863,  December  7th.     At  Tirlemont,  Belgium. 

7.  1863,  December  10th.  At  Inly,  near  Trebizond.* 


*  This  list  contains  nothing  but  aerolites.  In  the  Edinburgh  Re 
view  for  January,  1867,  we  find  the  following  statements:  "Out  of 
the  large  number  of  authentic  aerolites  preserved  in  mineralogical 
collections,  two  only — one  on  the  10th  of  August,  and  one  on  the 
13th  of  November — are  recorded  to  have  fallen  on  star-shower  dates. 
On  the  other  hand,  five  or  six  meteorites,  on  the  epoch  of  the  13th- 
14th  of  October,  belong  to  a  date  when  star-showers,  so  far  as  is  at 
present  known,  do  not  make  their  appearance."  The  inaccuracy  of 
the  former  statement  is  sufficiently  apparent.  In  regard  to  the  latter 
we  remark  that  Quetelet's  Catalogue  gives  one  star-shower  on  the 
14th  of  October,  and  another  on  the  12th. 


64  METEORIC    ASTRONOMY. 


IV.  The  Epoch  of  April  18th-26th. 

For  this  epoch  we  have  the  following  aerolites: 

1.  1803,  April  26th.     At  L'Aigle,  France. 

2.  1808,  April  19th.     At  Casignano,  Parma,  Italy. 
8.  1838,  April  18th.     At  Abkurpore,  India, 

4.  1842,  April  26th.     At  Milena,  Croatia. 

V.  The  Epoch  of  April  9th-12th. 

1.  1805,  April  10th.  At  Doroninsk,  Russia. 

2.  1812,  April  10th.  At  Toulouse,  France. 

3.  1818,  April  10th.  At  Zaborzika,  Russia. 

4.  1864,  April  12th.  At  ISTerft,  Russia. 

The  foregoing  lists,  which  might  be  extended,  are 
sufficient  to  establish  the  fact'  that  meteoric  stones 
are  but  the  largest  masses  in  the  nebulous  rings  from 
which  showers  of  shooting-stars  are  derived ;  a  fact 
worthy  of  consideration  whatever  theory  may  be 
adopted  in  regard  to  the  origin  of  such  annuli. 


UNIVERSITY 


CHAPTER  VI. 

PHENOMENA    SUPPOSED    TO    BE    METEORIC  —  METEORIC 
DUST  —  DARK    DAYS. 

IT  is  well  known  that  great  variety  has  been  found 
in  the  composition  of  aerolites.  While  some  are 
extremely  hard,  others  are  of  such  a  nature  as  to  be 
easily  reducible  to  powder.  It  is  not  impossible  that 
when  some  of  the  latter  class  explode  in  the  atmos 
phere  they  are  completely  pulverized,  so  that,  reach 
ing  the  earth  in  extremely  minute  particles,  they  are 
never  discovered.  It  is  very  unlikely,  moreover, 
that  of  the  millions  of  shooting-stars  that  daily  pene 
trate  the  atmosphere  nothing  whatever  in  the  solid 
form  should  ever  reach  the  earth's  surface.  Indeed, 
the  celebrated  Reiehenbach,  who  devoted  great  at 
tention  to  this  subject,  believed  that  he  had  actually 
discovered  such  deposits  of  meteoric  matter.  Chladni 
and  others  have  detailed  instances  of  the  fall  of  dust, 
supposed  to  be  meteoric,  from  the  upper  regions  of 
the  atmosphere.  The  following  may  be  regarded, 
with  more  or  less  probability,  as  instances  of  such 
phenomena: 

1.  A.D.  475,  November  5th  or  6th.  A  shower  of 
black  dust  fell  in  the  vicinity  of  Constantinople. 
Immediately  before  or  about  the  time  of  the  fall,  ac- 

6*  (  65  ) 


66  METEORIC    ASTRONOMY. 

cording  to  old  accounts,  "the  heavens  appeared  to 
be  on  fire,"  which  seems  to  indicate  a.  meteoric  dis 
play  of  an  extraordinary  character. 

2.  On  the  3d  of  December,  1586,  a  considerable 
quantity  of  dark-colored  matter  fell  from  the  atmos 
phere,  at  Yerde,  in  Hanover.    The  fall  was  attended 
by  intense  light,  as  well  as  by  a  loud  report  resem 
bling  thunder.     The  substance  which  fell  was  hot 
when  it  reached  the  earth,  as  the  planks  on  which 
a  portion  of  it  was  found  were  slightly  burnt,  or 
charred.     The   date  of  this   occurrence,  allowance 
being   made   for   the    movement   of    the    node,   is 
included  within  the  limits  of  the  meteoric  epoch  of 
December  6th-13th. 

3.  About  a  century  later,  viz.,  on  the  31st  of  Jan 
uary,  1686,   a  very   extensive   deposit  of  blackish 
matter,  in  appearance  somewhat  resembling  charred 
paper,  took  place  in  Norway  and  other  countries  in 
the  north  of  Europe.     A  portion  of  this  substance, 
which  had  been  carefully  preserved,  was  analyzed 
by  Grotthus,  and  found  to  contain  iron,  silica,  and 
other  elements  frequently  met  with  in  aerolites. 

4.  On  the  15th  of  November,  1755,  red  rain  fell  in 
Sweden  and  Russia,  and  on  the  same  day  in  Switzer 
land.     It  gave  a  reddish  color  to  the  waters  of  Lake 
Constance,  to  which  it  also  imparted  an  acid  taste. 
The  rain  which  fell  on  this  occasion  deposited  a 
sediment   whose   particles   were   attracted    by   the 
magnet. 

5.  In  1791  a  luminous  meteor  exploded  over  the 
Atlantic  Ocean,  and  at  the  same  time  a  quantity  of 
matter  resembling  sand  descended  to  the  surface. 

6.  According  to  Chladni  the  explosion  of  a  large 


PHENOMENA    SUPPOSED    TO    BE    METEORIC.  67 

bolide  over  Peru,  on  the  27th  of  August,  1792,  was 
followed  by  a  shower  of  cindery  matter,  the  fall  of 
which  continued  during  three  consecutive  days. 

7.  On  the  13th  and  14th  of  March,  1813,  a  shower 
of  red  dust  fell  in   Calabria,  Tuscany,   and  Friuli. 
The  deposit  was  sufficient  to  impart  its  color  to  the 
snow  which  was  then  upon  the  ground.     That  this 
dust  was  meteoric  can  scarcely  be  doubted,  since  at 
the  same  time  a  shower  of  aerolites  fell  at  Cutro,  in 
Calabria,  attended  by  two  loud  reports  resembling 
thunder.      The  shower  of  dust  continued  several 
hours,  and  was  accompanied  by  a  noise  which  was 
compared  to  the  distant  dashing  of  the  waves  of  the 
ocean.* 

8.  In  November,  1819,  black  rain  and  snow  fell  in 
Canada. 

9.  On  the   3d  of  May,  1831,  red  rain  fell  near 
Giessen.   It  deposited  a  dark-colored  sediment  which 
Dr.  Zimmermann  found  to  contain  silica,  oxide  of 
iron,  and  various  other  substances  observed  in  aero 
lites. 

It  is  well  known  that  quantities  of  sand  are  often 
conveyed,  by  the  trade-winds,  from  the  continent  of 


*  The  date  of  this  remarkable  occurrence  is  worthy  of  note  as  a 
probable  aerolite  epoch.  From  the  12th  to  the  15th  of  March  we 
have  the  following  falls  of  meteoric  stones: 

1.  1731,  March  12th.     At  Halstead,  Essex,  England. 

2.  1798,  March  12th.     At  Sale's,  France. 

3.  1806,  March  15th.     At  Alais,  France. 

4.  1807,  March  13th.     At  Timochin,  Russia. 

5.  1811,  March  13th.     At  Kuleschofka,  Russia. 

6.  1813,  March  13th-14th.     The  phenomena  above  described. 

7.  1841,  March  12th.     At  Gruneberg,  Silesia. 
Numerous  fire-balls  have  appeared  at  the  same  epoch. 


68  METEORIC    ASTRONOMY. 

Africa  and  deposited  in  the  ocean.  Such  sand- 
showers  have  sometimes  occurred  several  hundred 
miles  from  the  coast.  Volcanic  matter  also  has  "been 
occasionally  carried  a  considerable  distance.  The 
phenomena  above  described  cannot,  however,  be 
referred  to  such  causes;  and  there  can  be  little 
doubt  that  most,  if  not  all  of  them,  were  of  mete 
oric  origin. 

There  is,  in  all  probability,  a  regular  gradation 
from  the  smallest  visible  shooting- stars  to  bolides 
and  aerolites.  ~No  doubt  a  great  number  of  very 
small  meteoric  stones  penetrate  beneath  the  earth's 
surface  and  escape  observation.  An  interesting  ac 
count  of  the  accidental  discovery  of  such  celestial 
pebbles  has  recently  been  given  by  Professor  Haidin- 
ger,  of  Vienna.  The  meteor  from  which  they  were 
derived  ivas  but  little  larger  than  an  ordinary  shooting- 
star.  Its  track  was  visible,  however,  until  it  termin 
ated  at  the  earth's  surface.  Professor  Haidinger's 
account  is  as  follows:  On  the  31st  of  July,  1859, 
about  half-past  nine  o'clock  in  the  evening,  three 
inhabitants  of  the  bourg  of  Montpreis,  in  Styria,  saw 
a  small  luminous  globe,  very  similar  to  a  shooting- 
star,  and  followed  by  a  luminous  streak  in  the 
heavens,  fall  directly  to  the  earth,  which  it  attained 
close  to  the  chateau  that  exists  in  the  locality.  The 
fall  was  accompanied  by  a  whistling  or  hissing  noise 
in  the  air,  and  terminated  by  a  slight  detonation. 
The  three  observers,  rushing  to  the  spot  where  the 
meteor  fell,  immediately  found  a  small  cavity  in  the 
hard,  sandy  soil,  from  which  they  extracted  three 
small  meteoric  stones  about  the  size  of  nuts,  and  a 
quantity  of  black  powder.  For  five  to  eight  seconds 


PHENOMENA    SUPPOSED    TO    BE    METEORIC.  69 

these  stones  continued  in  a  state  of  incandescence,  and 
it  was  necessary  to  allow  upwards  of  a  quarter  of  an 
hour  to  elapse  before  they  could  be  touched  without 
inflicting  a  burn.  They  appear  to  have  been  ordi 
nary  meteoric  stones,  covered  with  the  usual  black 
rind.  The  possessors  would  not  give  them  up  to  be 
analyzed.  The  details  of  this  remarkable  occurrence 
of  the  fall  of  an  extremely  small  meteor,  we  owe  to 
Herr  Deschann,  Conservator  of  the  Museum  of  Lai- 
bach,  in  Carniola,  and  member  of  the  Austrian 
Chamber  of  Deputies. 

The  following  is  perhaps  the  only  instance  on  re 
cord  in  which  a  shooting-star  lower  than  the  clouds  has 
been  undoubtedly  observed.  The  date  is  one  at 
which  meteors  are  said  to  be  more  than  usually 
numerous;  and  the  radiant  point  for  the  epoch  has 
been  recently  determined,  by  British  observers,  to 
be  about  Gamma  Cygni.  The  meteor  was  seen  by 
Mr.  David  Trowbridge,  of  Hector,  Schuyler  County, 
~New  York,  who  says :  "  On  the  evening  of  July  26th, 
1866,  about  8h.  15m.  P.M.,  a  very  bright  meteor 
flashed  out  in  Cygnus,  and  moved  from  east  to  west 
with  great  rapidity.  Its  path  was  about  30°  after  I 
saw  it.  Height  above  the  northern  horizon  about 
50°.  Duration  of  flight  from  one-half  to  one  second. 
It  left  a  beautiful  train.  The  head  was  red  and  train 
blue.  It  was  certainly  below  the  clouds.  It  passed 
between  me  and  some  cirro-stratus  clouds,  so  dense 
as  to  hide  ordinary  stars  completely.  Several  others 
that  saw  it  said  it  was  below  the  clouds." — Sillimaris 
Journal  for  Sept,  1866.  It  seems  altogether  proba 
ble  that  when  a  meteor  thus  descends,  before  its  ex 
plosion  or  dissipation,  into  the  lower  atmospheric 


70  METEORIC    ASTRONOMY. 

strata,  at  least  portions  of  its  mass  must  reach  the 
earth's  surface. 

METEORIC  TRANSITS — DARK  DAYS. 

If  shooting-stars  and  aerolites  are  derived  from 
meteoric  rings  revolving  round  the  sun  in  orbits 
nearly  intersecting  that  of  the  earth,  then  (1)  these 
masses  must  sometimes  transit  the  solar  disk;  (2)  if 
any  of  the  rings  contain  either  individual  masses  of 
considerable  magnitude,  or  sufficiently  dense  swarms 
of  meteoric  asteroids,  such  transits  may  sometimes  be 
observed;  (3)  the  passage  of  a  dense  meteoric  cluster 
over  the  solar  disk  must  partially  intercept  the  sun's 
light  and  heat;  and  (4)  should  both  nodes  of  the  ring 
very  nearly  intersect  the  earth's  orbit,  meteoric  falls 
might  occur  when  the  earth  is  at  either;  in  which 
case  the  epochs  would  be  separated  by  an  interval  of 
about  six  months.  Have  any  such  phenomena  as 
those  indicated  been  actually  observed? 

The  passage  of  dark  spots  across  the  sun,  having 
a  much  more  rapid  motion  than  the  solar  maculse, 
has  been  frequently  noticed.  The  following  instances 
are  well  authenticated : 

1779,  June  17th.  About  mid-day  the  eminent 
French  astronomer,  Messier,  saw  a  great  number  of 
black  points  crossing  the  sun.  Rapidly  moving  spots 
were  also  seen  by  PastorfFon  the  following  dates: 

1822,  October  23d, 

1823,  July  24th  and  25th, 
1836,  October  18th, 

and  011  several  subsequent  occasions  the  same  as 
tronomer  witnessed  similar  phenomena.     Another 


PHENOMENA    SUPPOSED    TO    BE    METEORIC.  71 

transit  of  this  kind  has  been  seen  quite  recently.  On 
the  8th  of  May,  1865,  a  small  black  spot  was  seen 
by  Coumbary  to  cross  the  solar  disk.  It  seems  dif 
ficult  to  account  for  these  appearances  (so  frequently 
seen  by  experienced  observers)  unless  we  regard 
them  as  meteoric  masses. 

PARTIAL  INTERCEPTION  OF  THE  SUN'S  LIGHT  AND 
HEAT. 

Numerous  instances  are  on  record  of  partial  ob 
scurations  of  the  sun  which  could  not  be  accounted 
for  by  any  known  cause.  Cases  of  such  phenomena 
took  place,  according  to  Humboldt,  in  the  years  1090, 
1203,  and  1547.  Another  so-called  dark  day  occurred 
on  the  12th  of  May,  1706,  and  several  more  (some  of 
still  later  date)  might  be  specified.  Chladni  and 
other  physicists  have  regarded  the  transit  of  meteoric 
masses  as  the  most  probable  cause  of  these  obscura 
tions.  It  is  proper  to  remark,  however,  that  the 
eminent  French  astronomer,  Faye,  who  has  given 
the  subject  much  attention,  finds  little  or  no  evi 
dence  in  support  of  this  conjecture. 

An  examination  of  meteorological  records  is  said 
to  have  established  two  epochs  of  abnormal  cold,  viz., 
about  the  12th  of  February  and  the  12th  of  May. 
The  former  was  pointed  out  by  Brandes  about  the 
beginning  of  the  present  century;  the  latter  by 
Madler,  in  1834.  The  May  epoch  occurs  when  the 
earth  is  in  conjunction  with- one  of  the  nodes  of  the 
November  meteoric  ring;  and  that  of  February  has 
a  similar  relation  to  the  August  meteors.  M.  Erman, 
a  distinguished-  German  scientist,  soon  after  the  dis- 


72  METEORIC    ASTRONOMY. 

covery  of  the  August  and  November  meteoric  epochs, 
suggested  that  those  depressions  of  temperature  might 
be  explained  by  the  intervention  of  the  meteoric 
zones  between  the  earth  and  the  sun.  The  period, 
however,  of  the  November  meteors  being  still  some 
what  doubtful,  their  position  with  respect  to  the 
earth  about  the  12th  of  May  is  also  uncertain.  But 
however  this  may  be,  the  following  dates  of  aerolitic 
falls  seem  to  indicate  May  8th-14th,  or  especially 
May  12th-13th,  as  a  meteoric  epoch : 

(a)  May  8th,  1829,  Forsyth,  Georgia,  U.  S.  A. 

(b)  May  8th,  1846,  Macerate,  Italy. 

(c)  May  9th,  1827,  Nashville,  Tennessee,  U.  S.  A. 

(d)  May  12th,  1861,  Goruckpore,  India. 

(e)  May  13th,  1831,  Youilld,  France. 
(/)  May  13th,  1855,  Oesel,  Baltic  Sea. 

(g)  May  13th,  1855,  Brernevorde,  Hanover. 

(h)  May  14th,  1861,  near  Villanova,  in  Catalonia, 
Spain. 

({)  May  14th,  1864,  Orgueil,  France. 
All  the  foregoing,  except  that  of  May  14th,  1861, 
may  be  found  in  Shepard's  list,  Sillimaris  Journal  for 
January,  1867. 

It  has  been  shown  in  a  former  chapter  that  more 
than  seven  millions  of  shooting- stars  of  sufficient 
magnitude  to  be  seen  by  the  naked  eye  daily  enter 
the  earth's  atmosphere.  As  the  small  ones  are  the 
most  numerous,  it  is  not  improbable  that  an  indef 
initely  greater  number  of  meteoric  particles,  too 
minute  to  be  visible,  are  being  constantly,  in  this 
manner,  arrested  in  their  orbital  motion.  Now,  it 
would  certainly  be  a  very  unwarranted  conclusion 
that  these  atmospheric  increments  are  all  of  a  per- 


PHENOMENA    SUPPOSED    TO    BE    METEORIC.  73 

manently  gaseous  form.  In  view  of  this  strong 
probability  that  meteoric  dust  is  daily  reaching  the 
earth's  surface,  Baron  von  Reichenbach,  of  Vienna, 
conceived  the  idea  of  attempting  its  discovery.  As 
cending  to  the  tops  of  some  of  the  German  mountains, 
he  carefully  collected  small  quantities  of  the  soil  from 
positions  in  which  it  had  not  been  disturbed  by  man. 
This  matter,  on  being  analyzed,  was  found  to  con 
tain  small  portions  of  nickel  and  cobalt— elements 
rarely  found  in  the  mineral  masses  scattered  over 
the  earth's  surface,  but  very  frequently  met  with  in 
aerolites.  In  short,  Eeichenbach  believed,  and  cer 
tainly  not  without  some  probability,  that  he  had 
detected  minute  portions  of  meteoric  matter. 


CHAPTER  VII. 

FURTHER  RESEARCHES  OF  REICHENBACH  —  THEORY  OF 
METEORS STABILITY  OF  THE  SOLAR  SYSTEM  —  DOC 
TRINE  OF  A  RESISTING  MEDIUM. 

THE  able  and  original  researches  of  the  celebrated 
Reichenbach,  who  has  made  meteoric  phenomena 
the  subject  of  long-continued  and  enthusiastic  in 
vestigation,  have  attracted  the  general  attention  of 
scientific  men.  It  is  proposed  to  present,  in  the  fol 
lowing  chapter,  a  brief  resume  of  his  views  and  con 
clusions. 

1.  The  Constitution  of  Comets. — It  is  a  remarkable 
fact  that  cometary  matter  has  no  refractive  power, 
as  is  manifest  from  the  observations  of  stars  seen 
through  their  substance.*  These  bodies,  therefore, 
are  not  gaseous;  and  the  most  probable  theory  in 
regard  to  their  nature  is  that  they  consist  of  an  in 
finite  number  of  discrete,  solid  molecules,  at  great 
distances  from  each  other,  with  very  little  attraction 
among  themselves,  or  toward  the  nucleus,  and  hav 
ing,  therefore,  great  mobility.  Now  Baron  Reichen 
bach,  having  carefully  examined  a  great  number  of 
meteoric  stones,  has  found  them  for  the  most  part 

*  The  innermost  or  semi-transparent  ring  of  Saturn  appears  to 
be  similarly  constituted,  as  the  body  of  the  planet  is  seen  through  it 
without  any  distortion  whatever. 

(t4) 


FURTHER  RESEARCHES  OF  REICHENBACH.     75 

composed  of  extremely  minute  globules,  apparently 
cemented  together.  He  "hence  infers  that  they  have 
been  comets — perhaps  very  small  ones — whose  com 
ponent  molecules  have  by  degrees  collected  into 
single  masses. 

2.  The  Number  of  Aerolites. — The  average  number 
of  aerolitic  falls  in  a  year  was  estimated  by  Schreibers, 
as  previously  stated,  at  700.  Reichenbach,  however, 
after  a  thorough  discussion  of  the  data  at  hand,  makes 
the  number  much  larger.  He  regards  the  probable 
annual  average,  for  the  entire  surface  of  the  earth, 
as  not  less  than  4500.  This  would  give  about  twelve 
daily  falls.  They  are  of  every  variety  as  to  magni 
tude,  from  a  weight  of  less  than  a  single  ounce  to 
over  30,000  pounds.  The  Baron  even  suspects  the 
meteoric  origin  of  large  masses  of  dolerite  which  all 
former  geologists  had  considered  native  to  our  planet. 
In  view  of  the  fact  that  from  the  largest  members  of 
our  planetary  system  down  to  the  particles  of  mete 
oric  dust  there  is  an  approximately  regular  gradation, 
and  that  the  larger,  at  least  in  some  instances,  appear 
to  have  been  formed  by  the  aggregation  of  the 
smaller,  he  asks  may  not  the  earth  itself  have  been 
formed  by  an  agglomeration  of  meteorites?  The 
learned  author,  from  the  general  scope  of  his  specu 
lations,  would  thus  seem  to  have  adopted  a  form 
of  the  nebular  hypothesis  somewhat  different  from 
that  proposed  by  Laplace. 

3.  Composition  and  mean  Density  of  Aerolites. — A 
large  proportion  of  meteoric  stones  are  similar  in 
structure  to  the  volcanic  or  plutonic  rocks  of  the 
earth;  and  all  consist  of  elements  identical  with 
those  in  our  planet's  crust.  Their  mean  density, 


76  METEORIC    ASTRONOMY. 

moreover,  is  very  nearly  the  same  with  that  of  the 
earth.  These  facts  are  regarded  by  Reichenbach  as 
indicating  that  those  meteoric  masses  which  are 
daily  becoming  incorporated  with  our  planet,  have 
had  a  common  origin  with  the  earth  itself.  Baron 
Reichenbach's  views,  as  presented  by  himself,  will 
be  found  at  length  in  Poggmdorfs  Annalen  for  De 
cember,  1858. 

Stability  of  the  Solar  System. — The  well-known  dem 
onstrations  of  the  stability  of  the  solar  system, 
given  by  Lagrange  and  Laplace,  are  not  to  be  ac 
cepted  in  an  unlimited  sense.  They  make  no  provi 
sion  against  the  destructive  agency  of  a  resisting 
medium,  or  the  entrance  of  matter  into  the  solar 
domain  from  the  interstellar  spaces.  In  short,  the 
conservative  influence  ascribed  to  these  celebrated 
theorems  extends  only  to  the  major  planets;  and 
even  in  their  case  it  is  to  be  understood  as  applying 
only  to  their  mutual  perturbations.  The  phenomena 
of  shooting-stars  and  aerolites  have  demonstrated 
the  existence  of  considerable  quantities  of  matter 
moving  in  unstable  orbits.  The  amount  of  such  mat 
ter  within  the  solar  system  cannot  now  be  determ 
ined;  but  the  term  probably  includes  the  zodiacal 
light,  man}7,  if  not  all,  of  the  meteoric  rings,  and  a 
large  number  of  comets.  These  unstable  parts  of  the 
system  are  being  gradually  incorporated  with  the 
sun,  the  earth,  and  doubtless  also  with  the  other 
large  planets.  It  is  highly  probable  that  at  former 
epochs  the  quantity  of  such  matter  was  much  greater 
than  at  present,  and  that,  unless  new  supplies  be  re 
ceived  ab  extra,  it  must,  by  slow  degrees,  disappear 
from  the  system. 


DOCTRINES    OF    A    RESISTING    MEDIUM.  77 

The  fact,  now  well  established,  of  the  extensive 
diffusion  of  meteoric  matter  through  the  interplan 
etary  spaces  has  an  obvious  bearing  on  Encke's  theory 
of  a  resisting  medium.  If  we  grant  the  existence  of 
such  an  ether,  it  would  seem  unphilosophical  to  as 
cribe  to  it  one  of  the  properties  of  a  material  fluid — 
the  power  of  resisting  the  motion  of  all  bodies  mov 
ing  through  it — and  to  deny  it  such  properties  in 
other  respects.  Its  condensation,  therefore,  about 
the  sun  and  other  large  bodies  must  be  a  necessary 
consequence.  This  condensation  existed  in  the 
primitive  solar  spheroid,  before  the  formation  of  the 
planets:  the  rotation  of  the  spheroid  would  be  com 
municated  to  the  coexisting  ether;  and  hence,  during 
the  entire  history  of  the  planetary  system,  the  ether  has 
revolved  around  the  sun  in  the  same  direction  with  the 
planets.  This  condensed  ether,  it  is  also  obvious, 
must  participate  in  the  progressive  motion  of  the 
solar  system. 

But  again;  even  if  we  reject  the  doctrine  of  the 
development  of  the  planetary  bodies  from  a  rotating 
nebula,  we  must  still  regard  the  density  of  the  ether 
as  increasing  to  the  center  of  the  system.  The  sun's 
rotation,  therefore,  would  communicate  motion  to 
the  first  and  denser  portions;  this  motion  would  be 
transmitted  outward  through  successive  strata,  with 
a  constantly  diminishing  angular  velocity.  The 
motion  of  the  planets  themselves  through  the  me 
dium  in  nearly  circular  orbits  would  concur  in  im 
parting  to  it  a  revolution  in  the  same  direction. 
Whether,  therefore,  we  receive  or  reject  the  nebular 
hypothesis,  the  resistance  of  the  ethereal  medium  to 
bodies  moving  in  orbits  of  small  eccentricity  and 

7* 


78  METEORIC    ASTRONOMY. 

in  the  direction  of  the  sun's  rotation,  becomes  an 
infinitesimal  quantity. 

The  hypothesis  of  Encke,  it  is  well  known,  was 
based  solely  on  the  observed  acceleration  of  the 
comet  which  bears  his  name.  More  recently,  how 
ever,  a  still  greater  acceleration  has  been  found  in 
the  case  of  Faye's  comet.  Now  as  the  meteoric 
matter  of  the  solar  system  is  a  known  cause  for  such 
phenomena,  sufficient,  in  all  probability,  both  in 
mode  and  measure,  the  doctrine  of  a  resisting  ethe 
real  medium  would  seem  to  be  a  wholly  unnecessary 
assumption. 


CHAPTER    VIII. 

DOES  THE  NUMBER  OF  AEROLITIC  FALLS  VARY  WITH  THE 
EARTH'S  DISTANCE  FROM  THE  SUN? — RELATIVE  NUM 
BERS  OBSERVED  IN  THE  FORENOON  AND  AFTERNOON 

EXTENT    OF    THE    ATMOSPHERE    AS    INDICATED    BY  ME 
TEORS. 

AN  analysis  of  any  extensive  table  of  meteorites 
and  fire-balls  proves  that  a  greater  number  of  aero- 
litic  falls  have  been  observed  during  the  months  of 
June  and  July,  when  the  earth  is  near  its  aphelion, 
than  in  December  and  January,  when  near  its  peri 
helion.  It  is  found,  however,  that  the  reverse  is  true 
in  regard  to  bolides,  or  fire-balls.  Now  the  theory 
has  been  held  by  more  than  one  physicist,  that  aero 
lites  are  the  outriders  of  the  asteroid  ring  between 
Mars  and  Jupiter;  their  orbits  having  become  so 
eccentric  that  in  perihelion  they  approach  very  near 
that  of  the  earth.  If  this  theory  be  the  true  one,  the 
earth  would  probably  encounter  the  greatest  number 
of  those  meteor-asteroids  when  near  its  aphelion. 
The  hypothesis  therefore,  it  has  been  claimed,  ap 
pears  to  be  supported  by  well-known  facts.  The 
variation,  however,  in  the  observed  number  of  aero 
lites  may  be  readily  accounted  for  independently  of 

(79) 


80  METEORIC   ASTRONOMY. 

any  theory  as  to  their  origin.  The  fall  of  meteoric 
stones  would  evidently  be  more  likely  to  escape  ob 
servation  by  night  than  by  day,  by  reason  of  the 
relatively  small  number  of  observers.  But  the  days 
are  shortest  when  the  earth  is  in  perihelion,  and 
longest  when  in  aphelion :  the  ratio  of  their  lengths 
being  nearly  equal  to  that  of  the  corresponding  num 
bers  of  aerolitic  falls. 

On  the  other  hand,  it  is  obvious  that  fire-balls,  un 
less  of  very  extraordinary  magnitude,  would  not  be 
visible  during  the  day.  The  observed  number  will 
therefore  be  greatest  when  the  nights  are  longest; 
that  is,  when  the  earth  is  near  its  perihelion.  This, 
it  will  be  found,  is  precisely  in  accordance  with  ob 
servation. 

It  has  been  found,  moreover,  that  a  greater  num 
ber  of  meteoric  stones  fall  during  the  first  half  of  the 
day,  that  is,  from  midnight  to  noon,  than  in  the  lat 
ter  half,  from  noon  to  midnight.  This  would  seem 
to  indicate  that  a  large  proportion  of  the  aerolites 
encountered  by  the  earth  have  direct  motion. 

Height  of  the  Atmosphere. — The  weight  of  a  given 
volume  of  mercury  is  10,517  times  that  of  an  equal 
volume  of  air  at  the  earth's  surface;  and  since  the 
mean  height  of  the  mercurial  column  in  the  ba 
rometer  is  about  thirty  inches,  if  the  atmosphere 
were  of  uniform  density  its  altitude  would  be  about 
26,300  feet,  or  nearly  five  miles.  The  density  rap 
idly  diminishes,  however,  as  we  ascend  above  the 
earth's  surface.  Calling  it  unity  at  the  sea  level,  the 
rate  of  variation  is  approximately  expressed  as  fol 
lows: 


HEIGHT    OF    THE    ATMOSPHERE.  81 

Altitude  in  Miles.  Density. 

0        .......  1 

7        .......  i 

14        .        .        .    .     .        ...         .  TV 

21        .....        •        . 

28         ........  ^ 

35         ....... 


etc.  etc. 

From  this  table  it  will  be  seen  that  at  the  height  of 
35  miles  the  air  is  one  thousand  times  rarer  than  at 
the  surface  of  the  earth;  and  that,  supposing  the 
same  rate  of  decrease  to  continue,  at  the  height  of 
140  miles  the  rarity  would  be  one  trillion  times  greater. 
The  atmosphere,  however,  is  not  unlimited.  When  it 
becomes  so  rare  that  the  force  of  repulsion  between 
its  particles  is  counterbalanced  by  the  earth's  attrac 
tion,  no  further  expansion  is  possible.  To  determine 
the  altitude  of  its  superior  surface  is  a  problem  at 
once  difficult  and  interesting.  ~Not  many  years  since 
about  45  or  50  miles  were  generally  regarded  as  a 
probable  limit.  Considerable  light,  however,  has 
been  thrown  upon  the  question  by  recent  observa 
tions  in  meteoric  astronomy.  Several  hundred  det 
onating  meteors  have  been  observed,  and  their 
average  height  at  the  instant  of  their  first  appear 
ance  has  been  found  to  exceed  90  miles.  The  great 
meteor  of  February  3d,  1856,  seen  at  Brussels,  Gen 
eva,  Paris,  and  elsewhere,  was  150  miles  high  when 
first  seen,  and  a  few  apparently  well-authenticated 
instances  are  known  of  a  still  greater  elevation.  We 
conclude,  therefore,  from  the  evidence  afforded  by 


82  .METEORIC    ASTRONOMY. 

meteoric  phenomena,  that  the  height  of  the  atmos 
phere  is  certainly  not  less  than  200  miles. 

It  might  be  supposed,  however,  that  the  resistance 
of  the  air  at  such  altitudes  would  not  develop  a 
sufficient  amount  of  heat  to  give  meteorites  their 
brilliant  appearance.  This  question  has  been  dis 
cussed  by  Joule,  Thomson,  Haidinger,  and  Reichen- 
bach,  and  may  now  be  regarded  as  definitively  settled. 
When  the  velocity  of  a  meteorite  is  known  the 
quantity  of  heat  produced  by  its  motion  through  air 
of  a  given  density  is  readily  determined.  The  tem 
perature  acquired  is  the  equivalent  of  the  force  with 
which  the  atmospheric  molecules  are  met  by  the 
moving  body.  This  is  about  one  degree  (Fahren 
heit)  for  a  velocity  of  100  feet  per  second,  and  it 
varies  directly  as  the  square  of  the  velocity.  A 
velocity,  therefore,  of  30  miles  in  a  second  would 
produce  a  temperature  of  2,500,000°.  The  weight 
of  5280  cubic  feet  of  air  at  the  earth's  surface  is 
about  2,830,000  grains.  This,  consequently,  is  the 
weight  of  a  column  1  mile  in  length,  and  whose 
base  or  cross  section  is  one  square  foot.  The  weight 
of  a  column  of  the  same  dimensions  at  a  height  of 
140  miles  would  be  about  -3  smooth  of  a  grain.  Hence 
the  heat  acquired  by  a  meteoric  mass  whose  cross 
section  is  one  square  foot,  in  moving  1  mile  would 
be  one  grain  raised  7  4  degrees,  or  one-fifth  of  a  grain 
2500°  in  70  miles.  This  temperature  would  un 
doubtedly  be  sufficient  to  render  meteoric  bodies 
brilliantly  luminous. 

But  there  have  been  indications  of  an  atmosphere 
at  an  elevation  of  more  than  500  miles.  A  discus 
sion  of  the  best  observations  of  the  great  aurora  seen 


ATMOSPHERE'S  EXTENT  AS  INDICATED  BY  METEORS.     83 

throughout  the  United  States  on  the  28th  of  August, 
1859,  gave  534  miles  as  the  height  of  the  upper  limit 
above  the  earth's  surface.  The  aurora  of  September 
2d,  of  the  same  year,  had  an  elevation  but  little  in 
ferior,  viz.,  495  miles.  Now,  according  to  the  ob 
served  rate  of  variation  of  density,  at  the  height  of 
525  miles,  the  atmosphere  would  be  so  rare  that  a 
sphere  of  it  filling  the  orbit  of  Neptune  would  con 
tain  less  matter  than  aVth  of  a  cubic  inch  of  air  at 
the  earth's  surface.  In  other  words,  it  would  weigh 
less  than  ^Vth  of  a  grain.  We  are  thus  forced  to  the 
conclusion  either  that  the  law  of  variation  is  not  the 
same  at  great  heights  as  near  the  surface;  or,  that 
beyond  the  limits  of  the  atmosphere  of  air,  there  is 
another  of  electricity,  or  of  some  other  fluid. 


CHAPTER  IX. 

THE    METEORIC    THEORY    OF    SOLAR   HEAT. 

OF  the  various  theories  proposed  by  astronomers 
to  account  for  the  origin  of  the  sun's  light  and  heat, 
only  two  have  at  present  any  considerable  number 
of  advocates.  These  are — 

1.  The  Chemical  Theory ;  according  to  which  the 
light  and  heat  of  the  sun  are  produced  by  the  chemi 
cal  combination  of  its  elements;  in  other  words,  by 
an  intense  combustion. 

2.  The  Meteoric  Theory,  which  ascribes  the  heat  of 
our  centra]  luminary  to  the  fall  of  meteors  upon  its 
surface.     The  former  is  advocated  with  great  inge 
nuity  by  Professor  Ennis  in  a  recent  work  on  "  The 
Origin  of  the  Stars,  and  the  Causes  of  their  Motions  and 
their  Light"     It  has,  on  the  other  hand,  been  ably 
opposed  by  Dr.  Mayer,  Professor  William  Thomson, 
and  other  eminent  physicists.     A  brief  examination 
of  its  claims  may  not  be  destitute  of  interest. 

If  the  sun's  heat  is  produced  by  chemical  action, 
whence  comes  the  necessary  supply  of  fuel  to  support 
the  combustion  ?  The  quantity  of  solar  heat  radiated 
into  space  has  been  determined  with  at  least  an  ap 
proximation  to  mathematical  precision.  We  know 
also  the  amount  produced  by  the  combustion  of  a 
given  quantity  of  coal.  Now  it  has  been  found  by 
(84) 


THE    METEORIC    THEORY    OF    SOLAR    HEAT.  85 

calculation  that  if  the  sun  were  a  solid  globe  of  coal, 
and  a  sufficient  supply  of  oxygen  were  furnished  to 
support  its  combustion,  the  amount  of  heat  resulting 
from  its  consumption  would  be  less  than  that  actually 
emitted  during  the  last  6000  years.  In  short,  no 
known  elements  would  meet  the  demands  of  the 
case.  But  it  is  highly  probable  that  the  different 
bodies  of  the  solar  system  are  composed  of  the  same 
elements.  This  view  is  sustained  by  the  well-known 
fact  that  meteoric  stones,  which  have  reached  us 
from  different  and  distant  regions  of  space,  have 
brought  us  no  new  elementary  substances.  The 
chemical  theory  of  solar  heat  seems  thus  encumbered 
with  difficulties  well-nigh  insuperable. 

Professor  Ennis'  mode  of  obviating  this  objection, 
though  highly  ingenious,  is  by  no  means  conclusive. 
The  latest  analyses  of  the  solar  spectrum  indicate, 
he  affirms,  the  presence  of  numerous  elements  be 
sides  those  with  which  we  are  acquainted.  Some  of 
these  may  yield  by  their  combustion  a  much  greater 
amount  of  heat  than  the  same  quantity  of  any  known 
elements  in  the  earth's  crust.  "Every  star,"  he  re 
marks,  "  as  far  as  yet  known,  has  a  different  set  of 
fixed  lines,  although  there  are  certain  resemblances 
between  tliem.  They  lead  to  the  conclusion  that 
each  star  has,  in  part  at  least,  its  peculiar  modifica 
tions  of  matter,  called  simple  elements;  but  the 
number  of  stars  is  infinite,  and  therefore  the  num 
ber  of  elements  must  be  infinite."*  He  argues, 
moreover,  that  in  a  globe  so  vast  as  the  sun  there 
may  be  forces  in  operation  with  whose  nature  we 

*  Origin  of  the  Stars,  p.  173. 

8 


86  METEORIC    ASTRONOMY. 

are  wholly  unacquainted.  This  leaving  of  the  blown 
elements  as  well  as  the  known  laws  of  nature  for  un 
known  possibilities  will  hardly  be  satisfactory  to  un 
biased  minds. 

Again:  that  the  different  bodies  of  the  universe 
are  composed  of  different  elements  is  inferred  by  our 
author  from  the  following  among  other  considera 
tions  :  "  In  our  solar  system  Mercury  is  sixty  or  eighty 
times  more  dense  than  one  of  the  satellites  of  Jupiter, 
and  probably  in  a  much  greater  proportion  denser 
than  the  satellites  of  Saturn.  This  indicates  a  wide 
difference  between  the  nature  of  their  elements." 
This  statement  is  again  repeated  in  a  subsequent 
page.*  "  The  densities  of  the  planets  and  their 
satellites  prove  that  they  are  composed  of  very  dif 
ferent  elements.  Mercury  is  more  than  sixty  times, 
and  our  earth  about  fifty  times,  more  dense  than  the 
inner  moon  of  Jupiter.  Saturn  is  only  about  one- 
ninth  as  dense  as  the  earth ;  it  would  float  buoyantly 
on  water.  There  is  a  high  probability  that  the  satel 
lites  of  Saturn  and  Uranus  are  far  lighter  than  those 
of  Jupiter.  Between  the  two  extremes  of  the  attend 
ants  of  the  sun,  there  is  probably  a  greater  difference 
in  density  than  one  hundred  to  one;  and  from  one 
extreme  to  the  other  there  are  regular  gradations  of 
small  amount. 

"  The  difference  in  constitution  between  the  earth 
and  the  moon  is  seen  in  their  densities:  that  of  the 
moon  being  about  half  that  of  the  earth.  The 
nitrogen  of  our  globe  is  found  only  in  the  atmos 
phere,  and  such  substances  as  derive  it  from  the 

*  Origin  of  the  Stars,  p.  184. 


THE    METEORIC    THEORY    OF 

atmosphere.     The  moon  has  no 

phere,   and    therefore,   in   a   high   pfols^mrf^^jvm 

nitrogen."  fy?  t        * 

The  statements  here  quoted  were  desigtieB/^to 
show  that  the  physical  constitution  of  the  sun  and 
planets  is  widely  different  from  that  of  the  earth, 
and  that  the  combustion  of  some  of  the  elements  in 
this  indefinite  variety  may  account  for  the  origin  of 
solar  heat.  Let  us  examine  the  facts. 

According  to  Laplace  the  mass  of  Jupiter's  first 
satellite  is  0-000017328,  that  of  Jupiter  being  1.  The 
diameter  is  2436  miles.  Hence  the  corresponding 
density  is  a  little  more  than  one-fifth  of  the  mean 
density  of  the  earth.  In  other  words,  it  is  somewhat 
greater  than  the  density  of  water,  and  very  nearly 
equal  to  that  of  Jupiter  himself.  Professor  Ennis' 
value  is  therefore  erroneous.*  In  regard  to  the 
densities  of  the  Saturnian  and  Uranian  satellites 
nothing  is  known,  and  conjecture  is  useless.  In 
short,  Saturn  has  the  least  mean  density  of  all  the 
planets,  primary  or  secondary,  so  far  as  known. 
This  may  be  owing  to  the  great  extent  of  his  atmos 
pheric  envelope.  The  density  of  the  moon  is  but 
three-fifths  that  of  the  earth:  it  is  to  be  borne  in 
mind,  however,  that  the  mass  and  pressure  are  also 
much  less. 

With  respect  to  meteorites  the  same  author  re 
marks  that  "  like  the  moon,  they  are  probably  satel 
lites  of  the  earth;  but  being  very  small,  they  are 

*  Since  the  above  was  written  Prof.  Ennis  has  informed  the  author 
that,  without  making  any  estimate  of  his  own,  he  adopted  the 
density  of  Jupiter's  first  satellite  as  given  in  Lardnev's  Handbook  <>f 
Astronomy, 


88  METEORIC    ASTRONOMY. 

liable  to  extraordinary  perturbations,  and  hence 
strike  the  earth  in  many  directions."  Here,  again,  his 
facts  are  at  fault;  for  (1)  the  observed  velocities  of 
these  bodies  are  inconsistent  with  the  supposition  of 
their  being  satellites  of  the  earth;  and  (2)  the 
amount  of  perturbation  of  such  bodies  does  not  vary 
with  their  masses :  a  small  meteorite  would  fall 
toward  the  earth  or  any  other  planet  with  no  greater 
velocity  than  a  large  one. 

THE  METEORIC  THEORY. 

It  has  been  shown  in  a  previous  chapter  that  im 
mense  numbers  of  meteoric  asteroids  are  constantly 
traversing  the  planetary  spaces — that  many  millions, 
in  fact,  daily  enter  the  earth's  atmosphere.  Reasons 
are  not  wanting  for  supposing  the  numbers  of  these 
bodies  to  increase  with  great  rapidity  as  we  approach 
the  center  oi  the  system.  Moreover,  on  account  of 
the  greater  force  of  gravity  at  the  sun's  surface  the 
heat  produced  by  their  fall  must  be  much  greater 
than  at  the  surface  of  the  earth.  It  has  been  calcu 
lated  that  if  one  of  these  asteroids  be  arrested  in 
perihelion  by  the  solar  atmosphere,  the  quantity  of 
heat  thus  developed  will  be  9000  times  greater  than 
that  produced  by  the  combustion  of  an  equal  mass 
of  coal.  There  can,  therefore,  be  no  reasonable 
doubt  that  a  portion  of  the  sun's  heat  is  produced  by 
the  impact  of  meteoric  matter.  In  considering  the 
probability  that  it  is  chiefly  so  generated,  the  follow 
ing  questions  naturally  present  themselves  : 

1.  What  amount  of  matter  precipitated  upon  the  sun 
would  develop  the  quantity  of  heat  actually  emitted? — 


THE    METEORIC    THEORY.  89 

This  question  has  been  satisfactorily  discussed  by 
eminent  physicists,  and  it  will  be  sufficient  for  our 
purpose  to  give  the  result.  According  to  Professor 
William  Thomson,  of  Glasgow,  the  present  rate  of 
emission  would  be  kept  up  by  a  meteoric  deposit 
which  would  form  an  annual  stratum  60  feet  in 
thickness  over  the  sun's  surface. 

2.  Could  such  an  increase  of  the  sun's  magnitude  be 
detected  by  micrometrical  measurement? — This  inquiry 
is  readily  answered  in  the  negative.     The  apparent 
diameter  would  be  augmented  only  one  second  in 
17,600  years. 

3.  Is  there  any  known  or  visible  source  from  which 
this  amount  of  meteoric,  matter  may  be  supplied? — Thom 
son,  Mayer,  and  other  distinguished  writers  regard 
the  zodiacal  light  as  the  source  of  such  meteorites. 
The  inner  portions  of  this  immense  "tornado"  must 
be  resisted  in  their  motions  by  the  solar  atmosphere, 
and  hence  precipitated  upon  the  sun's  surface. 

4.  Would  this  increase  of  the  sun's  mass  derange  the 
motions  of  the  solar  system? — To  this  question  Prof. 
Ennis  gives  an  affirmative  answer;  his  first  objection 
to  the  theory  under  consideration  being  stated  as 
follows:   "The  constant  accumulation  of  such  ma 
terials,  during  hundreds  of  millions  of  years,  would 
increase  the  body  of  the  sun    and   its  consequent 
gravity  so  greatly  as  to  derange  the  entire  solar  sys 
tem,  by  destroying   the  balance  between   the  cen 
tripetal  and  centrifugal    forces  now  acting  on  the 
planets."*     This,  it  must  be  confessed,  would  be  a 
valid  objection,  if  the  meteoric  matter  were  sup- 


*  Origin  of  the  Stars,  p.  77. 


MKTEOHIC    ASTRONOMY. 

posed  to  be  derived  from  the  extra-planetary  spaces. 
As  their  source,  however, — the  zodiacal  light — is 
interior  to  the  earth's  orbit,  it  can  have  no  applica 
tion  to  any  planet  exterior  to  Venus.  Most  probably 
the  greater  portion  of  the  meteoric  mass  is  even 
within  the  orbit  of  Mercury,  so  that  the  effect  of  its 
convergence  could  scarcely  be  noticed  even  in  the 
motion  of  the  interior  planets.  In  pre-historic  time 
the  zodiacal  light  may  have  extended  far  beyond  the 
earth's  orbit.  If  so,  its  convergence  to  its  present 
dimensions  was  undoubtedly  attended  by  an  accel 
eration  of  the  earth's  mean  motion.  We  can  of 
course  have  no  evidence  that  such  a  shortening  of 
the  year  has  never  occurred. 

The  second  objection  urged  against  the  meteoric 
theory  by  the  author  of  "The  Origin  of  the  Stars" 
is  thus  expressed:  "As  we  must  believe  that  all  stars 
were  lighted  up  by  the  same  means,  so  we  must  be 
lieve,  according  to  this  theory,  that  the  present  inte 
rior  heat  of  the  earth  and  its  former  melted  condition 
in  both  exterior  and  interior,  was  caused  by  the  fall 
of  meteorites.  But  if  so,  they  must  have  gradually 
ceased  to  fall,  as  space  became  cleared  of  their  pres 
ence,  and  we  would  now  find  a  thick  covering  of 
meteorites  on  the  earth's  cooled  surface.  Instead  of 
this,  we  find  them  very  rarely,  and  in  accordance 
with  their  present  very  rare  falls." 

To  this  it  may  be  replied  that  the  primitive  igneous 
fluidity  of  the  earth  and  planets  was  a  necessary  con 
sequence  of  their  condensation — a  fact  which  has  no 
inconsistency  with  the  theory  in  question. 

A  different  mechanical  theory  of  the  origin  of  solar 
heat  is  advocated  by  Professor  Helmholtz  in  his  in- 


THE    METEORIC    THEORY.  91 

teresting  work  On,  the  Interaction  of  Natural  Forces. 
In  regard  to  the  sun  he  says:  "If  we  adopt  the  very 
probable  view,  that  the  remarkably  small  density  of 
so  large  a  body  is  caused  by  its  high  temperature, 
and  may  become  greater  in  time,  it  may  be  calcu 
lated  that  if  the  diameter  of  the  sun  were  diminished 
only  the  ten-thousandth  part  of  its  present  length,  by 
this  act  a  sufficient  quantity  of  heat  would  be  gen 
erated  to  cover  the  total  emission  for  2100  years. 
Such  a  small  change  besides  it  would  be  difficult  to 
detect  by  the  finest  astronomical  observations."* 
The  same  view  is  adopted  by  Dr.  Joel  E.  Hendricks, 
of  Des  Moines,  lowa.f 


*  Youman's  Correlation  and  Conservation  of  Forces,  p.  244. 

f  Iowa  Instructor  and  School  Journal  for  November,  1866,  p.  49. 


CHAPTER  X. 

WILL    THE    METEORIC    THEORY    ACCOUNT    FOR    THE    PHE 
NOMENA    OF   VARIABLE    AND    TEMPORARY    STARS? 

HAVING  shown  that  meteor-asteroids  are  diffused 
in  vast  quantities  throughout  the  universe;  that  ac 
cording  to  eminent  physicists  the  solar  heat  is  pro 
duced  by  the  precipitation  of  such  matter  on  the 
sun's  surface;  and  that  Leverrier  has  found  it  neces 
sary  to  introduce  the  disturbing  effect  of  meteoric 
rings  in  order  fully  to  account  for  the  motion  of 
Mercury's  perihelion;  we  now  propose  extending 
the  meteoric  theory  to  a  number  of  phenomena  that 
have  hitherto  received  no  satisfactory  explanation. 

VARIABLE  AND  TEMPORARY  STARS. 

No  theory  as  to  the  origin  of  the  sun's  light  and 
heat  would  seem  to  be  admissible  unless  applicable 
also  to  the  sidereal  systems.  Will  the  meteoric 
theory  explain  the  phenomena  of  variable  and  tem 
porary  stars? 

"It  has  been  remarked  respecting  variable  stars, 

that  in  passing  through  their  successive  phases,  they 

are  subject  to  sensible  irregularities,  which  have  not 

hitherto  been  reduced  to  fixed  laws       In  general 

(92) 


VARIABLE    AND    TEMPORARY    STARS.  93 

they  do  not  always  attain  the  same  maximum  bright 
ness,  their  fluctuations  being  in  some  cases  very 
considerable.  Thus,  according  to  Argelander,  the 
variable  star  in  Corona  Borealis,  which  Pigott  dis 
covered  in  1795,  exhibits  on  some  occasions  such 
feeble  changes  of  brightness,  that  it  is  almost  im 
possible  to  distinguish  the  maxima  from  the  minima 
by  the  naked  eye;  but  after  it  has  completed  several 
of  its  cycles  in  this  manner,  its  fluctuations  all  at 
once  become  so  considerable,  that  in  some  instances 
it  totally  disappears.  It  has  been  found,  moreover, 
that  the  light  of  variable  stars  does  not  increase  and 
diminish  symmetrically  on  each  side  of  the  maximum, 
nor  are  the  successive  intervals  between  the  maxima 
exactly  equal  to  each  other." — Grant' s  History  of  Phys 
ical  Astronomy,  p  541. 

Of  the  numerous  hypotheses  hitherto  proposed  to 
account  for  these  phenomena  we  believe  none  can  be 
found  to  include  and  harmonize  all  the  facts  of  ob 
servation.  The  theories  of  Herschel  and  Maupertius 
fail  to  explain  the  irregularity  in  some  of  the  periods; 
while  those  of  Newton  and  Dunn  afford  no  explana 
tion  of  the  periodicity  itself.*  But  let  us  suppose 
that  among  the  fixed  stars  some  have  atmospheres 
of  great  extent,  as  was  probably  the  case  with  the 
sun  at  a  remote  epoch  in  its  history.  Let  us  also 
suppose  the  existence  of  nebulous  rings,  like  those 
of  our  own  system,  moving  in  orbits  so  elliptical 


*  A  recent  hypothesis  in  regard  to  the  temporary  star  of  1572  has 
been  proposed  by  Alexander  Wilcocks,  M.D.,  of  Philadelphia.  See 
Journ.  Acad.  Nat.  Sci.  of  Phila.  for  1859. 


94  METEORIC    ASTRONOMY. 

that  in  their  perihelia  they  pass  through  the  atmos 
pheric  envelopes  of  the  central  stars.  Such  meteoric 
rings  of  varying  density,  like  those  revolving  about 
the  sun,  would  evidently  produce  the  phenomena  of 
variable  stars.  The  resisting  medium  through  which 
they  pass  in  perihelion  must  gradually  contract  their 
orbits,  or,  in  other  words,  diminish  the  intervals  be 
tween  consecutive  maxima.  Such  a  shortening  of 
the  period  is  now  well  established  in  the  case  of 
Algol.  Again,  if  a  ring  be  influenced  by  perturba 
tion  the  period  will  be  variable,  like  that  of  Mira 
Ceil.  A  change,  moreover,  in  the  perihelion  distance 
will  account  for  the  occasional  increase  or  diminution 
of  the  apparent  magnitude  at  the  different  maxima 
of  the  same  star.  But  how  are  we  to  account  for  the 
variations  of  brightness  observed  in  a  number  of 
stars  where  no  order  or  periodicity  in  the  variation 
has  as  yet  been  discovered  ?  It  is  easy  to  perceive 
that  either  a  single  nebulous  ring  with  more  than 
one  hiatus,  or  several  rings  about  the  same  star,  may 
produce  phenomena  of  the  character  described. 
Finally,  if  the  matter  of  an  elliptic  ring  should  ac 
cumulate  in  a  single  mass,  so  as  to  occupy  a  com 
paratively  small  arc,  its  passage  through  perihelion 
might  produce  the  phenomenon  of  a  so-called  tem 
porary  star. 

Recent  researches  relating  to  nebulae  seem  in  some 
measure  confirmatory  of  the  view  here  presented. 
These  observations  have  shown  (1)  a  change  of  posi 
tion  in  some  of  these  objects,  rendering  it  probable 
that  in  certain  cases  they  are  not  more  distant  than 
fixed  stars  visible  to  the  naked  eye;  and  (2)  a  varia- 


VARIABLE    AND    TEMPORARY    STARS.  95 

tion  in  the  brilliancy  of  many  small  stars  situated  in 
the  great  nebula  of  Orion,  and  also  the  existence  of 
numerous  masses  of  nebulous  matter  in  the  form  of 
tufts  apparently  attached  to  stars, — facts  regarded  as 
indicative  of  a  physical  connection  between  the  stars 
and  nebulae.* 

*  Gautier's  Notice  of  Recent  Researches  relating  to  Nebulae. — 
Silliman's  Journal  for  Jan.  1863,  and  March,  1864. 


CHAPTER   XI. 

THE    LUNAR    AND    SOLAR    THEORIES    OF    THE    ORIGIN    OF 
AEROLITES. 

BESIDES  the  cosmical  theory  of  aerolites  which  has 
been  adopted  in  this  work,  and  which  is  now  accepted 
by  a  great  majority  of  scientific  men,  at  least  four 
others  have  been  proposed:  (1)  the  atmospheric,  ac 
cording  to  which  they  are  formed,  like  hail,  in  the 
earth's  atmosphere;  (2)  the  volcanic,  which  regards 
them  as  matter  ejected  with  great  force  from  ter 
restrial  volcanoes ;  (3)  the  lunar,  which  supposes 
them  to  have  been  thrown  from  craters  in  the  moon; 
and  (4)  the  solar  hypothesis,  according  to  which  they 
are  projected  by  some  tremendous  explosive  force 
from  the  great  central  orb  of  our  system.  The  first 
and  second  have  been  universally  abandoned  as  un 
tenable.  The  third  and  fourth,  however,  are  entitled 
to  consideration. 

THE  LUNAR  THEORY. 

The  theory  which  regards  meteoric  stones  as  pro 
ducts  of  eruption  in  lunar  volcanoes  was  received 
with  favor  by  the  celebrated  Laplace:  "As  the 
gravity  at  the  surface  of  the  moon,"  he  remarks,  "is 
much  less  than  at  the  surface  of  the  earth,  and  as 
this  body  has  no  atmosphere  which  can  oppose  a 
(96) 


THE    LUNAR    THEORY.  97 

sensible  resistance  to  the  motion  of  projectiles,  we 
may  conceive  that  a  body  projected  with  a  great 
force,  by  the  explosion  of  a  lunar  volcano,  may 
attain  and  pass  the  limit,  where  the  attraction  of  the 
earth  commences  to  predominate  over  that  of  the 
moon.  For  this  purpose  it  is  sufficient  that  its  ini 
tial  velocity  in  the  direction  of  the  vertical  may  be 
2500  meters  in  a  second;  then  in  place  of  falling 
back  on  the  moon,  it  becomes  a  satellite  of  the  earth, 
and  describes  about  it  an  orbit  more  or  less  elon 
gated.  The  direction  of  its  primitive  impulsion  may 
be  such  as  to  make  it  move  directly  toward  the 
atmosphere  of  the  earth;  or  it  may  not  attain  it,  till 
after  several  and  even  a  great  number  of  revolu 
tions;  for  it  is  evident  that  the  action  of  the  sun, 
which  changes  in  a  sensible  manner  the  distances  of 
the  moon  from  the  earth,  ought  to  produce  in  the 
radius  vector  of  a  satellite  which  moves  in  a  very 
eccentric  orbit,  much  more  considerable  variations, 
and  thus  at  length  so  diminish  the  perigean  distance 
of  the  satellite,  as  to  make  it  penetrate  our  atmos 
phere.  This  body  traversing  it  with  a  very  great 
velocity,  and  experiencing  a  very  sensible  resistance, 
might  at  length  precipitate  itself  on  the  earth;  the 
friction  of  the  air  against  its  surface  would  be  suffi 
cient  to  inflame  it,  and  make  it  detonate,  provided 
that  it  contained  ingredients  proper  to  produce  these 
effects,  and  then  it  would  present  to  us  all  those 
phenomena  which  meteoric  stones  exhibit.  If  it  was 
satisfactorily  proved  that  they  are  not  produced  by 
volcanoes,  or  generated  in  our  atmosphere,  and  that 
their  cause  must  be  sought  beyond  it,  in  the  regions 
of  the  heavens,  the  preceding  hypothesis,  which 

9 


98  METEORIC    ASTRONOMY. 

likewise  explains  the  identity  of  composition  ob 
served  in  meteoric  stones,  by  an  identity  of  origin, 
will  not  be  devoid  of  probability." — Systeme  dn 
Monde,  t.  ii.  cap.  v. 

Knowing  the  masses  and  volumes  of  the  earth  and 
moon,  it  is  easy  to  estimate  the  force  of  gravity  at 
their  surfaces,  the  distance  from  each  to  the  point  of 
equal  attraction,  and  the  force  with  which  a  projectile 
must  be  thrown  from  the  lunar  surface  to  pass  within 
the  sphere  of  the  earth's  influence.  It  has  been  cal 
culated  that  an  initial  velocity  of  about  a  mile  and  a 
half  in  a  second  would  be  sufficient  for  this  purpose 
— a  force  not  greater  than  that  known  to  have  been 
exerted  by  terrestrial  volcanoes.  The  possibility, 
therefore,  that  volcanic  matter  from  our  satellite 
may  reach  the  earth's  surface  seems  fairly  admis 
sible. 

Since  the  time  of  Laplace,  several  distinguished 
European  astronomers  have  regarded  the  lunar  hy 
pothesis  as  more  or  less  probable.  It  was  advocated 
as  recently  as  1851  by  the  late  Prof.  J.  P.  Mchol,  of 
Glasgow.  This  popular  and  interesting  writer,  after 
describing  Tycho,  a  large  and  well-known  lunar 
crater,  from  which  luminous  rays  or  stripes  radiate 
over  a  considerable  part  of  the  moon's  surface,  ex 
presses  the  opinion  that  that  immense  cavity  was 
formed  by  a  single  tremendous  explosion.  "  Reflect 
ing,"  he  remarks,  "  on  the  probable  suddenness  and 
magnitude  of  that  force,  or  rather  of  that  explosive 
energy  one  of  whose  acts  we  have  traced,  as  well  as 
on  the  immense  mass  of  matter  which  seems  to  have 
been  thus  violently  dispersed,  is  not  the  inquiry  a 
natural  one,  where  is  that  matter  now  ?  It  is  a  mass 


THE    LUNAR    THEORY.  99 

indeed  which  cannot  well  have  wholly  disappeared. 
It  filled  a  cavern  55  miles  in  breadth,  and  17,000 
feet  deep — a  cavern  into  which  even  now  one  might 
cast  Chimborazo  and  Mont  Blanc,  and  room  be  left 
for  Teneriffe  behind!  Like  rocks  flung  aloft  by  our 
volcanoes,  did  this  immense  mass  fall  back  in  frag 
ments  to  the  surface  of  the  moon,  or  was  the  expul 
sive  force  strong  enough  to  give  it  an  outward  ve 
locity  sufficient  to  resist  the  attractive  power  of  its 
parent  globe?  The  moon,  be  it  recollected,  is  very 
small  in  mass  compared  with  the  earth,  and  her  at 
tractive  energy  greatly  inferior  accordingly.  Laplace 
has  even  calculated  that  the  force  urging  a  cannon- 
ball,  increased  to  a  degree  quite  within  the  limits  of 
what  is  conceivable,  could  effect  a  final  separation 
between  our  satellite  and  any  of  its  component 
parts.  It  is  possible  then,  and,  although  not  demon 
strable,  very  far  from  a  chimera,  that  the  disrupted 
and  expelled  masses  were,  in  the  case  of  which  we 
are  speaking,  driven  conclusively  into  space;  but  if 
so,  where  are  they  now?  where  their  new  residence, 
and  what  their  functions?  In  the  emergency  to 
which  I  refer,  such  fragments  would  necessarily 
wander  among  the  inter-planetary  spaces  in  most 
irregular  orbits,  and  chiefly  in  the  neighborhood  of 
the  moon  and  the  earth.  Now,  while  the  planetary 
orbits  are  so  nicely  adjusted  that  neither  confusion 
nor  interference  can  ever  occur,  it  is  not  at  all  likely 
that  the  same  order  could  be  established  here ;  nay, 
it  is  next  to  certain,  that  in  the  course  of  its  orbital 
revolution  our  globe  would  ever  and  anon  come  in 
contact  with  these  lunar  fragments;  in  other  words, 
STONES  would  fall  occasionally  to  its  surface,  and  ap- 


100  METEORIC    ASTRONONY. 

parently  from  its  atmosphere." — Planetary  System,  pp. 
301,  302. 

We  have  preferred  to  give  the  views  of  these 
eminent  scientists  in  their  own  language.  Olbers, 
Biot,  and  Poisson,  who  adopted  the  same  theory, 
estimated  the  initial  velocity  which  would  be  neces 
sary  in  order  that  lunar  fragments  might  pass  the 
point  of  equal  attraction,  and  also  the  final,  or  ac 
quired  velocity  on  reaching  the  earth's  surface'.  The 
several  determinations  of  the  former  were  as  fol 
lows: 

According  to  Olbers 1-570  miles  a  second. 

«  Biot 1-569     "  " 

Laplace 1-483     « 

"  Poisson 1-437     " 

The  mean  being  almost  exactly  a  mile  and  a  half. 
The  velocity  on  reaching  our  planet,  according  to 
Olbers,  would  be  about  six  and  a  half  miles.  At  the 
date  of  these  calculations,  however,  the  true  velocity 
of  aerolites  had  not  been  in  any  case  satisfactorily 
determined.  Since  that  time  it  has  been  found  in 
numerous  instances  to  exceed  twenty  miles  a  second — 
a  velocity  greater  than  that  of  the  earth's  orbital 
motion.  This  fact  of  itself  would  seem  fatal  to  the 
theory  of  a  lunar  origin. 

At  the  meeting  of  the  American  Association  for 
the  Advancement  of  Science,  in  1859,  Dr.  B.  A. 
Gould  read  a  paper  on  the  supposed  lunar  origin  of 
aerolites,  in  which  the  hypothesis  was  subjected  to 
the  test  of  a  rigid  mathematical  analysis.  We  will 
not  attempt  even  an  abstract  of  this  interesting 
memoir.  It  amounts,  however,  to  a  virtual  disproof 
of  the  lunar  hypothesis. 


THE    SOLAE    THEORY.  101 


THE  SOLAR  THEORY. 

The  theory  which  ascribes  a  solar  origin  to  me 
teorites  is  not  of  recent  date,  having  been  held  by 
Diogenes  Laertius  and  other  ancient  Greeks.  Among 
the  moderns  its  advocates  have  been  much  less  nu 
merous  than  those  of  the  lunar  hypothesis.  The  late 
Professor  Charles  W.  Hackley,  of  New  York,  re 
garded  shooting-stars,  aerolites,  and  even  comets,  as 
matter  projected  with  enormous  force  from  the  solar 
surface.  The  corona  seen  during  total  eclipses  of 
the  sun  he  supposed  to  be  the  emanations  of  this 
matter  through  the  intervals  of  the  luculi. — (See  the 
Proceedings  of  the  American  Association  for  the  Ad 
vancement  of  Science,  Fourteenth  Meeting,  1860.) 
An  ingenious  theory,  differing  in  its  details  from 
that  of  Professor  Hackley,  though  somewhat  similar 
in  its  general  features,  has  lately  been  advocated 
by  Alexander  Wilcocks,  M.D.,  of  Philadelphia,  in  a 
memoir  read  before  the  American  Philosophical 
Society,  May  20th,  1864,  and  published  in  their  Pro 
ceedings.  In  regard  to  this  hypothesis  it  seems  suf 
ficient  to  remark  that  it  fails  to  give  a  satisfactory 
account  of  the  annual  periodicity  of  meteoric  phe 
nomena. 


9* 


CHAPTEE  XII. 

THE    RINGS    OF    SATURN. 

UNTIL  about  the  middle  of  the  present  century  the 
rings  of  Saturn  were  universally  regarded  as  solid 
and  continuous.  The  labors,  however,  of  Professors 
Bond  and  Pierce,  of  Cambridge,  Massachusetts,  as 
well  as  the  more  recent  investigations  of  Prof.  Max 
well,  of  England,  have  shown  this  hypothesis  to  be 
wholly  untenable.  The  most  probable  opinion,  based 
on  the  researches  of  these  astronomers,  is,  that  they 
consist  of  streams  or  clouds  of  meteoric  asteroids. 
The  zodiacal  light  and  the  zone  of  small  planets  be 
tween  Mars  and  Jupiter  appear  to  constitute  analo 
gous  primary  rings.  In  the  latter,  however,  a  large 
proportion  of  the  primitive  matter  seems  to  have 
collected  in  distinct,  segregated  masses.  These 
meteoric  zones  have  probably  presented — what  are 
not  elsewhere  found  in  the  solar  system — cases  of 
commensurability  in  the  planetary  periods.  The 
interior  satellites  of  Saturn  are  so  near  the  ring  as 
doubtless  to  exert  great  perturbative  influence.  Un 
fortunately,  the  elements  of  the  Saturnian  system  as 
determined  by  different  astronomers  are  somewhat 
discordant.  This,  however,  is  by  no  means  sur 
prising  when  we  consider  the  great  distance  of  the 
(102) 


THE    RINGS    OF    SATURN. 


ioa 


planet  and  the  small  magnitude  of  some  of  the  satel 
lites.  For  convenience  of  reference  the  mean  ap 
parent  distances  of  the  satellites,  together  with  their 
periodic  times,  are  given  in  the  following  table.  The 
former  are  taken  from  Hind's  Solar  System;  the  latter 
from  Herschel's  Outlines  of  Astronomy. 

TABLE  I,— THE  SATELLITES  OF  SATURN. 


NAME. 

SIDEREAL  REVOLUTION. 

MEAN  APPARENT 
DISTANCE. 

Mimas 

d.        h.      m.        s. 
0     22     37     22-9 

it 

26-78 

Enceladus 

1       8     53       6-7 

34-38 

Tethys        

1     21     18     95.7 

42-57 

Dione         

2     17     41       8-9 

54-54 

Rhea  

4     12     25     10-8 

76-16 

Titan  

15     22     41     25-2 

176-55 

Hyperion  

22     12'' 

213-3? 

Japetus  

79       7     53     40-4 

514-52 

The  late  Professor  Bessel  devoted  much  attention 
to  the  theory  of  Titan,  whose  mean  distance  he  found 
to  be  20*706  equatorial  radii  of  the  primary.  Struve?s 
measurements  of  the  ring  .are  given  in  the  second 
column  of  the  following  table.  Sir  John  Herschel, 
however,  regards  the  Russian  astronomer's  interval 
between  the  rings  as  "somewhat  too  small."*  This 
remark  is  confirmed  by  the  measurements  of  Encke, 
whose  results  are  given  in  column  third.  The  fourth 
contains  the  mean  of  Struve's  and  Encke's  measure 
ments;  and  the  fifth,  the  same,  expressed  in  equa 
torial  radii  of  Saturn. 


Outlines  of  Astronomy,  Art.  442. 


104 


METEORIC   ASTRONOMY. 


TABLE  II,— THE  RINGS  OF  SATURN. 


STKUVE. 

ENCKE. 

MEAN. 

IN  SEMI-DIAM. 
OP  SATURN. 

Equatorial  radius  of 
the  planet 

// 

8-9955 

// 

// 

Ext.  semi-diameter  of 
exterior  ring  

20-047 

20-2225 

20-13475 

2-23830 

Int.  semi-diameter  of 
exterior  ring  

17-644 

18-0190 

17-83150 

1-98230 

Ext.  semi-diameter  of 
interior  ring 

17-237 

17-3745 

17-30575 

1-9°380 

Int.  semi  diameter  of 
interior  rin0" 

13-334 

13-3780 

13-35600 

1-48470 

Breadth  of  interval... 

00-407 

00-6445 

00-52575 

0-05844 

The  period  of  a  satellite  revolving  at 
the  distance,  1-9238,  the  interior  limit 
of  the  interval          ....  =10h.  50m. 
One-sixth  of  the  period  of  Dione        .  =10     56 
One-third  "  Enceladus.  =10     59 

One-half  "  Mimas       .  =11     18 

One-fourth          "  Tethys       .  =11     19 

And  the  period  of  a  satellite  at  the  dis 
tance,  1-9823,  the  exterior  limit  of 
the  interval  .  .  =11 


16s. 

53 

22 

32 

36 


28         3 

The  interval,  therefore,  occupies  precisely  the  space 
in  which  the  periods  would  be  commensurable  with 
those  of  the  four  members  of  the  system  immediately 
exterior.  Particles  occupying  this  portion  of  the 
primitive  ring  would  always  come  into  conjunction 
with  one  of  these  satellites  in  the  same  parts  of  their 
orbits.  Such  orbits  would  become  more  and  more 
eccentric  until  the  matter  moving  in  them  would 
unite  near  one  of  the  apsides  with  other  portions 
of  the  ring.  We  have  thus  a  physical  came  for  the  ex 
istence  of  thi*  remarkable  interval. 


CHAPTER  XIII. 

THE    ASTEROID    RING    BETWEEN    MARS    AND    JUPITER. 

THE  mean  distances  of  the  minor  planets  between 
Mars  and  Jupiter  vary  from  2-20  to  349.  The 
breadth  of  the  zone  is  therefore  20,000,000  miles 
greater  than  the  distance  of  the  earth  from  the  sun ; 
greater  even  than  the  entire  interval  between  the 
orbits  of  Mercury  and  Mars.  Moreover,  the  perihe 
lion  distance  of  some  members  of  the  group  exceeds 
the  aphelion  distance  of  others  by  a  quantity  equal  to 
the  whole  interval  between  the  orbits  of  Mars  and 
the  earth.  The  Olbersian  hypothesis  of  the  origin  of 
these  bodies  seems  thus  to  have  lost  all  claim  to 
probability.*  Professor  Alexander's  theory  of  the 
disruption  of  a  primitive  discoidal  planet  of  great 
equatorial  diameter,  is  less  objectionable;  still,  how 
ever,  it  requires  confirmation.  But  whatever  may 
have  been  the  original  constitution  of  the  ring,f  its 
existence  in  its  present  form  for  an  indefinite  period 

*  A  learned  and  highly  interesting  examination  of  this  hypothesis 
will  be  found  in  a  memoir  "On  the  Secular  Variations  and  Mutual 
Relations  of  the  Orbits  of  the  Asteroids,"  communicated  to  the  Am. 
Acad.  of  Arts  and  Sciences,  April  24th,  1860,  by  Simon  Newcomb, 
Esq. 

|  For  an  explanation  of  the  origin  of  the  asteroids  according  to 
the  nebular  hypothesis,  see  an  article  by  David  Trowbridge,  A.M., 
in  Silliman's  Journal  for  Nov.  1864,  and  Jan.  1865. 

(105) 


106  METEORIC    ASTRONOMY. 

is  unquestioned.  Let  us  then  consider  some  of  the 
effects  of  its  secular  perturbation  by  the  powerful 
mass  of  Jupiter. 

Portions  of  the  ring  in  which  the  periods  of  asteroids 

would  be  commensurable  with  that  of  Jupiter. The 

breadth  of  this  zone  is  such  as  to  contain  several 
portions  in  which  the  periods  of  asteroids  would  be 
commensurable  with  that  of  Jupiter.  As  in  the  case 
of  the  perturbation  of  Saturn's  ring  by  the  interior 
satellites,  the  tendency  of  Jupiter's  influence  would 
be  to  form  gaps  or  chasms  in  the  primitive  ring. 

The  mean  distance  of  an  asteroid  whose  period 

is  £  that  of  Jupiter =3-2776 

That  of  one  whose  period  is  $  of  Jupiter's       .  =2-5012 
I  "  .  =2-8245 

f  "  .  =2-2569 

f  "  .  =2-9574 

|  "  .  =3-0299 

For  the  purpose  of  facilitating  the  comparison  of  these 
numbers  with  the  mean  distances  of  the  asteroids 
and  of  observing  whether  any  order  obtains  in  the 
distribution  of  these  mean  distances  in  space,  we 
have  arranged  the  minor  planets,  in  the  following 
table,  in  the  consecutive  order  of  their  periods: 


ASTEROID    RING    BETWEEN    MARS   AND    JUPITER.       107 


Periods  and  Distances  of  the  Asteroids. 


ORDER  OP 
DISCOVERY. 


NAME. 


8  Flora 22014 

43  Ariadne 22034 

72  Feronia 2-2654 

40  Harmonia 2-2677 

18  Melpomene 2-2956 

80  Sappho 2-2971 

12  Victoria 2-3342 

27  Euterpe 2-3468 

4  Vesta 2-3613 

84  Clio '  2-3618 

30  Urania 2-3655 

51  Nemausa 2-8657 

9  Metis 2-3858 

7  Iris 23863 

60  Echo 2-3931 

63  Ausonia 2-3949 

25  Phocea 2-4008 

20  Massilia 2-4144 

67  Asia 2-4217 

44  Nysa 2-4234 

6  Hebe 2-4244     | 

83  Beatrice 2-4287 

42  Isis 24400 

21  Lutetia 2-4411 

19  Fortuna 2-4416 

79  Eurynome 2-4437 

11  Parthenope 2-4519 

17  Thetis 2-4737 

46  Hestia 2-5262 

89  2-5498 

29  Amphitrite 2-5544 

5  Astrsea 2-5772 

13  Egeria 2-5775 

14  Irene 2-5860 

32  Pomona 2-5868 

91  2-5958 

56  Melete 2-5959 

70  Panopea 2-6129 

53  Calypso 2-6188 

78  Diana 2-6236 

23  Thalia 2-6280 

37  Fides 2-6414 

15  Eunomia 26436 

85  lo 2-6466 

50  Virginia 2-6491 


DISTANCE. 


PERIOD. 


1193d 
1194-6 
1245-4 
1247-3 
1270-4 
1271-6 
1302-6 
1313-2 
1325-3 
1325-8 
1328-9 
1329-0 
13460 
1346-5 
1352-2 
1353-8 
1358-8 
1365-5 
1376-5 
1378-0 
1379-0 
1382-5 
1392-2 
1393-0 
1393-5 
1395-3 
1402-4 
1421-1 
1466-5 
1487-2 
1491-2 
1511-2 
1511-4 
1519-0 
1519-6 
1527-5 
1527-7 
1543-0 
1548-0 
1555-3 
1568-0 
1570-0 
1572-6 
1573-0 
1575-0 


108 


METEORIC    ASTRONOMY. 


Periods  and  Distances  of  the  Asteroids — Continued. 


ORDER  OF 
DISCOVERT. 

NAME. 

DISTANCE. 

PERIOD. 

88 

Thisbe  

2-6553 

1580-0 

26 

Proserpina  

2-6561 

1581-1 

66 

Maia  

2-6635 

1587-8 

73 

Clytie  

2-6666 

1590-5 

3 

Juno 

2-6707 

1594-2 

75 

Eurydice  . 

2-6707 

1594-2 

77 

f  rio-o-a  .  .. 

2-6719 

1595-3 

64 

Angelina  

2-6805 

1603-0 

34 

Circe  

2-6865 

1608-3 

58 

Concordia  

2  7014 

1622-0 

54 

Alexandra  

2-7123 

1631-6 

59 

Elpis 

2-7131 

•  1632-3 

45 

Eugenia 

2-7218 

1640-1 

38 

Leda  .       . 

2-7401 

1656-8 

36 

Atalanta.  .              

2-7458 

1662-0 

71 

Niobe  

2  7501 

1665-8 

82 

Alcniene  

2-7547 

1670-0 

55 

Pandora  

2-7591 

1674-0 

41 

Daphne 

2-7657 

1679-9 

1 

Ceres 

2-7663 

1681-0 

2 

Pallas 

2-7696 

1683-5 

39 

Laetitia  

2-7740 

1687-6 

74 

Galatea  

2-7777 

1690-9 

28 

Bellona  

2-7785 

1691-6 

68 

Leto  

2-7836 

1696-3 

81 

Terpsichore 

2-8591 

1765-7 

33 

Polyhymnia 

2-8653 

1770-6 

47 

Aglaia       ...                 

2-8812 

1786-4 

22 

Calliope  

2-9092 

1812-4 

16 

Psyche  

2  9233 

1826-0 

69 

Hesperia  

2-9707 

1871-1 

61 

D<inae 

2-9837 

1882-4 

35 

Leucothea 

3-0040 

1904-2 

49 

Pales 

3-0825 

1976-6 

86 

Semele                  

3-0909 

1984-7 

52 

Europa       

3-1000 

1993-6 

48 

Doris  

3-1094 

2002-7 

62 

Erato 

3-1297 

2022-3 

24 

Themis 

3-1431 

2035-3 

10 

Hvoieia 

3-1512 

2043-2 

31 

Euphrosyne  

3-1513 

20446 

57 

Mnemosyne  

3-1565 

2048-4 

90 

3-1576 

2049-4 

76 

Freia 

3-3864 

2276-2 

65 

Cybele           

3-4205 

2310-6 

87 

Sylvia     

3-4927 

2384-2 

ASTEROID    RING    BETWEEN    MARS    AND    JUPITER.       109 


REMARKS  ON  THE  FOREGOING  TABLE. 

1.  The  first  two  members  of  the  group,  Flora  and 
Ariadne,  have  very  nearly  the  same  mean  distance. 
Immediately  exterior  to  these,  however,  occurs  a 
wide  interval,  including  the  distance  at  which  seven 
periods  of  an  asteroid  would  be  equal  to  two  of 
Jupiter. 

2.  On  the  outer  limit  of  the  ring  Freia,  Cybele,  and 
Sylvia  have  also  nearly  equal  distances,  and  are  sep 
arated  from  the  next  interior  member  by  a  wide 
space  including  the  distance  at  which  two  periods 
would  be  equal  to  one  of  Jupiter,  and  also  that  at 
which  five  would  be  equal  to  one  of  Saturn. 

3.  Besides  these  extreme  members  of  the  group, 
our  table  contains  eighty-six  minor  planets,  all  of 
which  are  included  between  the  distances  2-26  and 
3-16;  the  mean  interval  between  them  being  0-0105. 
The  distances  are  distributed  as  follows: 

2-26  to  2-36 6     minimum. 

2-36  to  2  46 19     maximum. 

2-46  to  2-56 4     minimum. 

2-56  to  2-66 16lmaximum. 

2-66  to  2  76 16J 

2-76  to  2  86 8 

2-86  to  2-96 4lminimum. 

2-96  to  3-06 3  J 

3-06  to  3-16 10     maximum. 

The  clustering  tendency  is  here  quite  apparent. 

4.  The  three  widest  intervals  between  these  bodies 
are — 

(a)  between  Leucothea  and  Pales 0-0785, 

(b)  "         Leto  and  Terpsichore 0-0755, 

(c)  "         Thetis  and  Hestia 0-0525; 

10 


110  METEORIC    ASTRONOMY. 

and  these,  it  will  be  observed,  are  the  three  remain 
ing  distances,  indicated  on  a  previous  page,  at  which 
the  periods  of  the  primitive  meteoric  asteroids  would 
be  commensurable  with  that  of  Jupiter.  Now,  if 
the  original  ring  consisted  of  an  indefinite  number 
of  separate  particles  moving  with  different  velocities, 
according  to  their  respective  distances,  those  revolv 
ing  at  the  distance  2-4935 — in  the  interval  between 
Thetis  and  Hestia — would  make  precisely  three  rev 
olutions  while  Jupiter  completes  one.  A  planetary 
particle  at  this  distance  would  therefore  always  come 
in  conjunction  with  Jupiter  in  the  same  parts  of  its 
path:  consequently  its  orbit  would  become  more 
and  more  eccentric  until  the  particle  itself  would 
unite  with  others,  either  exterior  or  interior,  thus 
forming  an  asteroidal  nucleus,  while  the  primitive 
orbit  of  the  particle  would  be  left  destitute  of  matter, 
like  the  interval  in  Saturn's  ring. 

5.  If  the  distribution  of  matter  in  the  zone  was 
originally  nearly  continuous,  as  in  the  case  of  Saturn's 
rings,  it  would  probably  break  up  into  a  number  of 
concentric  annuli.  On  account,  however,  of  the 
great  perturbations  to  which  they  were  subject,  these 
narrow  rings  would  frequently  come  in  collision. 
After  their  rupture,  and  while  the  fragments  were 
collecting  in  the  form  of  asteroids,  numerous  inter 
sections  of  orbits  and  new  combinations  of  matter 
would  occur,  so  as  to  leave,  in  the  present  orbits, 
but  few  traces  of  the  rings  from  which  the  existing 
asteroids  were  derived.  A  comparison,  however,  of 
the  elements  of  Clytie  and  Frigga  shows  a  striking 
similarity;  and  Professor  Lespiault  has  pointed  out 
a  corresponding  likeness  between  the  orbits  of  Fides 


ASTEROID    RING    BETWEEN    MARS    AND   JUPITER.      Ill 

and  Maia.  For  these  four  asteroids  the  nodal  lines  and 
also  the  inclinations  are  nearly  the  same;  while  the 
periods  differ  by  only  a  few  days.  It  is  probable, 
therefore,  that  they  are  all  fragments  of  the  same 
narrow  ring.  Finally,  as  they  all  move  nearly  in  the 
same  plane,  they  must  at  some  future  time  approach 
extremely  near  each  other,  and  perhaps  become 
united  in  one  large  asteroid. 


CHAPTER  XIV. 

ORIGIN    OF    METEORS — THE    NEBULAR    HYPOTHESIS. 

IN  regard  to  the  physical  history  of  those  meteoric 
masses  which,  in  such  infinite  numbers,  traverse  the 
interplanetary  spaces,  our  knowledge  is  exceedingly 
limited.  Such  as  have  reached  the  earth's  surface 
consist  of  various  elements  in  a  state  of  combination. 
It  has  been  remarked,  however,  by  a  distinguished 
scientist*  that  "the  character  of  the  constituent 
particles  of  meteorites,  and  their  general  microscop 
ical  structure,  differ  so  much  from  what  is  seen  in 
terrestrial  volcanic  rocks,  that  it  appears  extremely 
improbable  that  they  were  ever  portions  of  the  moon, 
or  of  a  planet,  which  differed  from  a  large  meteorite 
in  having  been  the  seat  of  a  more  or  less  modified 
volcanic  action."  As  the  celebrated  nebular  hypoth 
esis  seems  to  afford  a  very  probable  explanation  of 
the  origin  of  those  bodies,  whether  in  the  form  of 
rings  or  sporadic  masses,  its  brief  consideration  may 
not  be  destitute  of  interest.  We  will  merely  pre 
mise  that  the  existence  of  true  nebulae  in  the  heavens 
— that  is,  of  matter  consisting  of  luminous  gas — has 
been  placed  beyond  doubt  by  the  revelations  of  the 
spectroscope. 

*  H.  C.  Sorby,  F.R.S. 
(112) 


ORIGIN    OF    METEORS.  113 

As  a  group,  our  solar  system  is  comparatively 
isolated  in  space;  the  distance  of  the  nearest  fixed 
star  being  at  least  seven  thousand  times  that  of 
Neptune,  the  most  remote  known  planet.  Besides 
the  central  or  controlling  orb,  it  contains,  so  far  as 
known  at  present,  ninety-nine  primary  planets, 
eighteen  satellites,  three  planetary  rings,  and  nearly 
eight  hundred  comets.  In  taking  the  most  cursory 
view  of  this  system  we  cannot  fail  to  notice  the  fol 
lowing  interesting  facts  in  regard  to  the  motions  of 
its  various  members: 

1.  The  sun  rotates  on  his  axis  from  west  to  east. 

2.  The  primary  planets  all  move  nearly  in  the 
plane  of  the  sun's  equator. 

3.  The  orbital  motions  of  all  the  planets,  primary 
and  secondary,  except  the  satellites  of  Uranus  and 
Neptune,  are  in  the  same  direction  with  the  sun's 
rotation. 

4.  The  direction  of  the  rotary  motions  of  all  the 
planets,  primary  and  secondary,  in  so  far  as  has  been 
observed,  is  identical  with  that  of  their  orbital  rev 
olutions;  viz.,  from  west  to  east. 

5.  The  rings  of  Saturn  revolve  about  the  planet 
in  the  same  direction. 

6.  The  planetary  orbits  are  all  nearly  circular. 

7.  The  cometary  is  distinguished  from  the  planetary 
portion  of  the  system  by  several  striking  character 
istics:  the  orbits  of  comets  are  very  eccentric  and 
inclined  to  each  other,  and  to  the  ecliptic  at  all  pos 
sible  angles.     The  motions  of  a  large  proportion  of 
comets  are/rom  east  to  west.     The  physical  constitu 
tion  of  the  latter  class  of  bodies  is  also  very  different 
from  that  of  the  former;  the  matter  of  which  comets 

10* 


114  METEORIC    ASTRONOMY. 

are  composed  being  so  exceedingly  attenuated,  at 
least  in  some  instances,  that  fixed  stars  have  been 
distinctly  visible  through  what  appeared  to  be  the 
densest  portion  of  their  substance. 

None  of  these  facts  are  accounted  for  by  the  law 
of  gravitation.  The  sun's  attraction  can  have  no  in 
fluence  whatever  in  determining  either  the  direction 
of  a  planet's  motion,  or  the  eccentricity  of  its  orbit. 
In  other  words,  this  power  would  sustain  a  planetary 
body  moving  from  east  to  west,  as  well  as  from  west 
to  east;  in  an  orbit  having  any  possible  degree  of 
inclination  to  the  plane  of  the  sun's  equator,  no  less 
than  in  one  coincident  with  it;  or,  in  a  very  eccen 
tric  ellipse,  as  well  as  in  one  differing  but  little  from 
a  circle.  The  consideration  of  the  coincidences 
which  we  have  enumerated  led  Laplace  to  conclude 
that  their  explanation  must  be  referred  to  the  mode 
of  our  system's  formation — a  conclusion  which  he 
regarded  as  strongly  confirmed  by  the  contemporary 
researches  of  Sir  William  Herschel.  Of  the  numer 
ous  nebulae  discovered  and  described  by  that  emi 
nent  observer,  a  large  proportion  could  not,  even  by 
his  powerful  telescope,  be  resolved  into  stars.  In 
regard  to  many  of  these,  it  was  not  doubted  that 
glasses  of  superior  power  would  show  them  to  be 
extremely  remote  sidereal  clusters.  On  the  other 
hand,  a  considerable  number  were  examined  which 
gave  no  indications  of  resolvability.  These  were 
supposed  to  consist  of  self-luminous,  nebulous  mat 
ter — the  chaotic  elements  of  future  stars.  The  great 
number  of  these  irresolvable  nebulae  scattered  over 
the  heavens  and  apparently  indicating  the  various 
stages  of  central  condensation,  very  naturally  sug- 


ORIGIN    OF    METEORS.  115 

gested  the  idea  that  the  solar  system,  and  perhaps 
every  other  system  in  the  universe,  originally  existed 
in  a  similar  state.    The  sun  was  supposed  by  Laplace 
to  have  been  an  exceedingly  diffused,  rotating  neb 
ula,  of  spherical  or  spheroidal  form,  extending  be 
yond  the  orbit  of  the  most  distant  planet;  the  planets 
as  yet  having  no  separate  existence.    This  immense 
sphere  of  vapor,  in  consequence  of  the  radiation  of 
heat  and  the  continual  action  of  gravity,  became 
gradually  more  dense,  which  condensation  was  ne 
cessarily  attended  by  an  increased  angular  velocity 
of  rotation.     At  length  a  point  was  thus  reached 
where  the  centrifugal  force  of  the  equatorial  parts 
was  equal  to  the  central  attraction.     The  condensa 
tion  of  the  interior  meanwhile  continuing,  the  equa 
torial  zone  was  detached,  but  necessarily  continued 
to  revolve  around  the  central  mass  with  the  same 
velocity  that  it  had  at  the  epoch  of  its  separation.  If 
perfectly  uniform  throughout  its  entire  circumfer 
ence,  which  would  be  highly  improbable,  it  would 
continue    its    motion    in    an    unbroken   ring,    like 
that  of  Saturn;   if  not,  it  would  probably  collect 
into  several  masses,  having  orbits  nearly  identical. 
"These  masses  should  assume  a  spheroidal  form, 
with  a  rotary  motion  in  the  direction  of  that  of  their 
revolution,  because  their  inferior  articles  have  a  less 
real  velocity  than  the  superior;  they  have  therefore 
constituted  so  many  planets  in  a  state  of  vapor.   But 
if  one  of  them  was  sufficiently  powerful  to  unite 
successively  by  its  attraction  all  the  others  about  its 
center,  the  ring  of  vapors  would  be  changed  into 
one  spheroidal  mass,  circulating  about  the  sun,  with 
a  motion  of  rotation  in  the  same  direction  with  that 


116  METEORIC    ASTRONOMY. 

of  revolution."*  Such,  according  to  the  theory  of 
Laplace,  is  the  history  of  the  formation  of  the  most 
remote  planet  of  our  system.  That  of  every  other, 
both  primary  and  secondary,  would  be  precisely 
similar. 

In  support  of  the  nebular  hypothesis,  of  which  the 
foregoing  is  a  brief  general  statement,  we  remark 
that  it  furnishes  a  very  simple  explanation  of  the  motions 
and  arrangements  of  the  planetary  system.  In  the  first 
place,  it  is  evident  that  the  separation  of  a  ring  would 
take  place  at  the  equator  of  the  revolving  mass,  where 
of  course  the  centrifugal  force  would  be  greatest. 
These  concentric  rings — and  consequently  the  result 
ing  planets — would  all  revolve  in  nearly  the  same  plane. 
It  is  evident  also  that  the  central  body  must  have  a 
revolution  on  its  axis  in  the  same  direction  with  the  pro 
gressive  motion  of  the  planets.  Again :  at  the  breaking 
up  of  a  ring,  the  particles  of  nebulous  matter  more 
distant  from  the  sun  would  have  a  greater  absolute 
velocity  than  those  nearer  to  it,  which  would  pro 
duce  the  observed  unity  of  direction  in  the  rotary  and 
orbital  revolutions.  The  motions  of  the  satellites  are 
explained  in  like  manner.  The  hypothesis,  more 
over,  accounts  satisfactorily  for  the  fact  that  the  orbits 
of  the  planets  are  all  nearly  circular.  And  finally, 
it  presents  an  obvious  explanation  of  the  rings  of 
Saturn.  It  would  almost  seem,  indeed,  as  if  these 
wonderful  annul!  had  been  left  by  the  Architect  of 
Nature,  as  an  index  to  the  creative  process. 

The  argument  derived  from  the  motions  of  the 
various  members  of  the  solar  system  is  not  new, 

*  Harte's  Trans,  of  Laplace's  Syst.  of  the  World,  vol.  ii.,  note  vii. 


ORIGIN    OF    METEORS.  117 

having  been  forcibly  stated  by  Laplace,  Pontdcou- 
lant,  Nichol,  and  other  astronomers.  Its  full  weight 
and  importance,  however,  have  not,  we  think,  been 
duly  appreciated.  That  a  common  physical  cause 
has  determined  these  motions,  must  be  admitted  by 
every  philosophic  mind.  But  apart  from  the  nebu 
lar  hypothesis,  no  such  cause,  adequate  both  in 
mode  and  measure,  has  ever  been  suggested; — in 
deed  none,  it  seems  to  us,  is  conceivable.  The  phe 
nomena  which  we  have  enumerated  demand  an  ex 
planation,  and  this  demand  is  met  by  the  nebular 
hypothesis.  It  will  be  found,  therefore,  when  closely 
examined,  that  the  evidence  afforded  by  the  celestial 
motions  is  sufficient  to  give  the  theory  of  Laplace  a 
very  high  degree  of  probability. 

A  comparison  of  the  facts  known  in  regard  to 
comets,  falling-stars,  and  meteoric  stones,  seems  to 
warrant  the  inference  that  they  are  bodies  of  the 
same  nature,  and  perhaps  of  similar  origin;  differ 
ing  from  each  other  mainly  in  the  accidents  of  mag 
nitude  and  density.  The  hypothesis  of  Laplace  very 
obviously  accounts  for  the  formation  of  planets  and 
satellites,  moving  in  the  same  direction,  and  in  orbits 
nearly  circular;  but  how,  it  may  be  asked,  can  the 
same  theory  explain  the  extremely  eccentric,  and  in 
some  cases  retrograde,  motions  of  comets  and  aero 
lites?  This  is  the  question  to  which  we  now  direct 
our  attention. 

After  the  nuclei  of  the  solar  and  sidereal  systems 
had  been  established  in  the  primitive  nebula,  and 
when,  in  consequence,  immense  gaseous  spheroids 
had  collected  around  such  nuclei,  we  may  suppose 
that  about  the  points  of  equal  attraction  between 


118  METEORIC   ASTRONOMY. 

the  sun  and  neighboring  systems,  portions  of  nebu 
lous  matter  would  be  left  in  equilibrio.  Such  out 
standing  nebulosities  would  gradually  contract 
through  the  operation  of  gravity;  and  if,  as  would 
sometimes  be  the  case,  the  solar  attraction  should 
preponderate,  they  would  commence  falling  toward 
our  system.  Unless  disturbed  by  the  planets  they 
would  probably  move  round  the  sun  in  parabolas. 
Should  they  pass,  however,  near  any  of  the  large 
bodies  of  the  system,  their  orbits  might  be  changed 
into  ellipses  by  planetary  perturbation.  Such  was 
the  view  of  Laplace  in  regard  to  the  origin  of 
comets. 

It  seems  probable,  however,  that  many  of  these 
bodies  originated  within  the  solar  system,  and  belong 
properly  to  it.  The  outer  rings  thrown  off  by  the 
planets  may  have  been  at  too  great  distances  from 
the  primaries  to  form  stable  satellites.  Such  masses 
would  be  separated  by  perturbation  from  their 
respective  primaries,  and  would  revolve  round  the 
sun  "in  independent  orbits.  Again:  small  portions 
of  nebulous  matter  may  have  been  abandoned  as 
primary  rings,  at  various  intervals  between  the 
planetary  orbits.  At  particular  distances  such  rings 
would  be  liable  to  extraordinary  perturbations,  in 
consequence  of  which  their  orbits  would  ultimately 
assume  an  extremely  elliptical  form,  like  those  of 
comets,  and  perhaps  also  those  of  meteors.  It  was 
shown  in  Chapter  XIII.  that  several  such  regions 
occur  in  the  asteroid  zone  between  Mars  and  Ju 
piter.  We  may  add,  in  confirmation  of  this  view, 
that  there  are  twelve  known  comets  whose  periods 
are  included  between  those  of  Flora  and  Jupiter. 


ORIGIN    OF    METEORS.  119 

Their  motions  are  all  direct;  their  orbits  are  less 
eccentric  than  those  of  other  comets;  and  the  mean 
of  their  inclinations  is  about  the  same  as  that  of  the 
asteroids.  These  facts  certainly  appear  to  indicate 
some  original  connection  between  these  bodies  and 
the  zone  of  minor  planets. 

The  nebular  hypothesis,  it  is  thus  seen,  accounts 
satisfactorily  for  the  origin  of  comets,  aerolites, 
fire-balls,  shooting-stars,  and  meteoric  rings ;  regard 
ing  them  all  as  bodies  of  the  same  nature,  moving 
in  cometary  orbits  about  the  sun.  In  this  theory, 
the  zodiacal  light  is  an  immense  swarm  of  meteor- 
asteroids;  so  that  the  meteoric  theory  of  solar  heat, 
explained  in  a  previous  chapter,  finds  its  place  as  a 
part  of  the  same  hypothesis. 


CONCLUSION. 


SOME  of  the  prominent  results  of  observation  and 
research  in  meteoric  astronomy  may  be  summed  up 
as  follows : 

1.  The  shooting-stars  of  November,  August,  and 
other  less  noted  epochs,  are  derived  from  elliptic 
rings  of  meteoric  matter  which  intersect  the  earth's 
orbit. 

2.  Meteoric  stones  and  the  matter  of  shooting-stars 
coexist  in  the  same  rings;  the  former  being  merely 
collections  or  aggregations  of  the  latter. 

3.  The  most  probable  period  of  the  November 
meteors   is   thirty-three  years   and   three   months. 
Leverrier's  elements  of  this  ring  agree  so  closely 
with  Oppolzer's  elements  of  the  comet  of  1866  as 
to  render  it  probable  that  the  latter  is  merely  a  large 
meteor  belonging  to  the  same  annulus. 

4.  The  spectroscopic  examination  of  this  comet 
(of  1866)    by  "William  Huggins,  F.K.S.,  indicated 
that  the  nucleus  was  self-luminous,  that  the  coma 
was  rendered  visible  by  reflecting  solar  light,  and 
that  "the  material  of  the  comet  was  similar  to  the 
matter  of  which  the  gaseous  nebulae  consist." 

5.  The  time  of  revolution  of  the  August  meteors 
is  believed  to  be  about  105  years.     M.  Schiaparelli 
has  found  a  striking  similarity  between  the  elements 
of  this  ring  and  those  of  the  third  comet  of  1862. 
The    same    distinguished    astronomer    has    shown, 

(120) 


CONCLUSION.  121 

moreover,  that  a  nebulous  mass  of  considerable  ex 
tent,  drawn  into  the  solar  system  ab  extra,  would 
form  a  ring  or  stream. 

6.  The  aerolitic  epochs,  established  with  more  or 
less  certainty,  are  the  following: 

1.  February  15th-19th. 

2.  March  12th-15th. 

3.  April  10th-12th. 

4.  April  18th-26th. 

5.  May  8th-14th;  or  especially,  12th-13th. 

6.  May  19th. 

7.  July  13th-14th. 

8.  July  26th. 

9.  August  7th-llth. 

10.  October  13th-14th. 

11.  November  llth-14th. 

12.  November  27th-30th. 

13.  December  7th-13th. 

About  one-half  of  this  number  are  also  known  as 
shooting-star  epochs. 

7.  The  epoch  of  November  27th-30th  corresponds 
with  that  of  the  earth's  crossing  the  orbit  of  Biela's 
two  comets.     The  aerolites  of  this  epoch  may  there 
fore  have  been  moving  in  nearly  the  same  path. 

8.  A  greater  number  of   aerolitic  falls   are   ob 
served — 

1.  By  day  than  by  night. 

2.  In  the  afternoon  than  in  the  forenoon. 

3.  When  the  earth  is  in  aphelion  than  when  in  perihelion. 

The  first  fact  is  accounted  for  by  the  difference  in 
the  number  of  observers;  the  second  indicates  that  a 
majority  of  aerolites  have  direct  motion;  and  the 
third  is  dependent  on  the  relative  lengths  of  the 

11 


122  METEORIC    ASTRONOMY. 

day  and  night  in  the  aphelic  and  perihelic  portions 
of  the  orbit. 

9.  The  observed  velocities  of  meteorites  are  in 
compatible  with  the  theory  of  their  lunar  origin. 

10.  If  the  meteoric  swarm  of  November  14th  has 
a  period  of  thirty-three  years,  Biela's  comet  passed 
very  near,  if  not  actually  through  it  toward  the  close 
of  1845,  about  the  time  of  the  comet's  separation. 
Was  the  division  of  the  cometary  mass  produced  by 
the  encounter? 

11.  The  rings  of  Saturn  may  be  regarded  as  dense 
meteoric  masses,  and  the  principal  or  permanent 
division  accounted  for  by  the  disturbing  influence 
of  the  interior  satellites. 

12.  The  asteroidal  space  between  Mars  and  Jupiter 
is  probably  a  wide  meteoric  ring  in  which  the  largest 
aggregations  are  visible  as  minor  planets.     In  the 
distribution  of  the  mean  distances   of  the  known 
members  of  the  group  a  clustering  tendency  is  quite 
obvious. 

13.  The  meteoric  masses  encountered  by  Encke's 
comet  may  account  for  the  shortening  of  the  period 
of  the  latter  without  the  hypothesis  of  an  ethereal 
medium. 


APPENDIX. 


A. 

The  Meteors  of  November  14th. 

The  American  Journal  of  Science  and  Arts  for  May, 
186T  (received  by  the  author  after  the  first  chapters  of  this 
work  had  gone  to  press),  contains  an  interesting  article  by 
Professor  Newton  "On  certain  recent  contributions  to  Astro- 
Meteorology."  Of  the  five  possible  periods  of  the  Novem 
ber  ring,  first  designated  by  Professor  N  ,  it  is  now  granted 
that  the  longest,  viz.,  33^  years,  is  most  probably  the  true 
one.  The  results  of  Leverrier's  researches  in  regard  to  the 
epoch  at  which  this  meteoric  mass  was  introduced  into  the 
solar  system,  are  given  in  the  same  article.  This  distin 
guished  astronomer  supposes  the  group  of  meteors  to  have 
been  thrown  into  an  elliptic  orbit  by  the  disturbing  influ 
ence  of  Uranus.  The  meteoric  stream,  according  to  the 
most  trustworthy  elements  of  its  orbit,  passed  extremely 
near  that  planet  about  the  year  126  of  our  era  ;  which  date 
is  therefore  assigned  by  Leverrier  as  the  probable  time  of 
its  entrance  into  the  planetary  system.  This  result,  how 
ever,  requires  confirmation. 

Although  the  earliest  display  of  the  November  meteors, 
so  far  as  certainly  known,  was  that  of  the  year  902,  several 
more  ancient  exhibitions  may,  with  some  probability,  be 
referred  to  the  same  epoch.  The?e  are  the  phenomena  of 
532,  599,  and  COO,  A.D.,  and  17G8,  B.C.  (See  Quetelet's 

(123) 


124  APPENDIX. 

Catalogue.)  The  time  of  the  year  at  which  these  showers 
occurred  is  not  given.  The  years,  however,  correspond 
very  well  with  the  epochs  of  the  maximum  display  of  the 
November  meteors.  The  intervals  arranged  in  consecutive 
order,  are  as  follows : 

From  B.C.  1768  to  A.D.    532,  69  periods  of  33-319  years  each. 

"     A.D.    532  (o  "  5995,  2  «  33-750 

"       "      599-5  to  "  902,  9  "  33-614 

"       902  to  "  934,'  1  "  32-000 

934  to  "  1002,  2    t    "  34-000 

"     1002  to  "  1101,  3  "  33-000 

"       "     1101  to  "  1202,  3  «  33667 

"     1202  to  "  1366,  5  "  32-800           " 

"       "     1366  lo  "  1533,  5  «  33-400 

"     1533  to  "  1698,  5  "  33000           " 

"       "     1698  to  "  1799,  3  "  33  667 

"     1799  to  "  1833,  1  "  34000 

"     1833  to  "  1866,  1  "  33-000 

The  first  three  dates  are  alone  doubtful.  The  whole  num 
ber  of  intervals  from  B.C.  1768  to  A.D.  1866  is  109,  and  the 
mean  length  is  33*33 'years. 

The  perturbations  of  the  ring  by  Jupiter,  Saturn,  and 
Uranus,  are  doubtless  considerable.  It  is  worthy  of  note 
that— 

14  periods  of  Jupiter  are  nearly  equal  to    5  of  the  ring. 

9         "  S»iturn         "  "          8 

23         "  Uranus        "  "        58 

This  group  or  stream  has  its  perihelion  at  the  orbit  of 
the  earth;  its  aphelion,  at  that  of  Uranus.  (See  diagram, 
p.  24.)  It  must  therefore  produce  star-showers  at  the  latter 
as  well  as  at  the  former.  Our  planet,  moreover,  at  each 
encounter  appropriates  a  portion  of  the  meteoric  matter; 
while  at  the  remote  apsis  of  the  stream  Uranus  in  all  prob 
ability  does  the  same.  The  matter  of  the  ring  will  thus  by 
slow  degrees  be  gathered  up  by  the  two  planets. 


APPENDIX.  125 


B. 

Comets  and  Meteors. 

The  recent  researches  and  speculations  of  European  as 
tronomers  in  regard  to  the  origin  of  comets  and  of  meteoric 
streams,  have  suggested  to  the  author  the  propriety  of  re 
producing  the  following  extracts  from  an  article  written  by 
himself,  in  July,  1861,  and  published  in  the  Danville  Quar 
terly  Review  for  December  of  that  year: 

"  Different  views  are  entertained  by  astronomers  in  regard 
to  the  origin  of  comets  ;  some  believing  them  to  enter  the 
solar  system  ab  extra;  others  supposing  them  to  have 
originated  within  its  limits.  The  former  is  the  hypothesis 
of  Laplace,  and  is  regarded  with  favor  by  many  eminent 
astronomers.  It  seems  to  afford  a  plausible  explanation  of 
the  paucity  of  large  comets  during  certain  long  intervals  of 
time.  In  one  hundred  and  fifty  years,  from  1600  to  H50, 
sixteen  comets  were  visible  to  the  naked  eye;  of  which 
eight  appeared  in  the  twenty-five  years  from  1664  to  1689. 
Again,  during  sixty  years  from  1750  to  1810,  only  five 
comets  were  visible  to  the  naked  eye,  while  in  the  next  fifty 
years  there  were  double  that  number.  Now,  according  to 
Laplace's  hypothesis,  patches  of  nebulous  matter  have  been 
left  nearly  in  equilibrium  in  the  interstellar  spaces.  As  the 
sun,  in  his  progressive  motion,  approaches  such  clusters, 
they  must,  by  virtue  of  his  attraction,  move  toward  the 
center  of  our  system;  the  nearer  portions  with  greater 
velocity  than  the  more  remote.  The  nebulous  fragments 
thus  introduced  into  our  system  would  constitute  comets  ; 
those  of  the  same  cluster  would  enter  the  solar  domain  at 
periods  not  very  distant  from  each  other  ;  the  forms  of  their 

11* 


12t)  APPENDIX. 

orbits  depending  upon  their  original  relative  positions  with 
reference  to  the  sun's  course,  and  also  on  planetary  perturb 
ations.  On  the  other  hand,  the  passage  of  the  system 
through  a  region  of  space  destitute  of  this  chaotic  vapor 
would  be  followed  by  a  corresponding  paucity  of  comets. 

"  Before  the  invention  of  the  telescope,  the  appearance  of 
a  comet  was  a  comparatively  rare  occurrence.  The  whole 
number  visible  to  the  naked  eye  during  the  last  three  hun 
dred  and  sixty  years  has  been  fifty-five  ;  or  a  mean  of  fifteen 
per  century.  The  recent  rate  of  telescopic  discovery,  how 
ever,  has  been  about  four  or  five  annually.  As  many  of 
these  are  extremely  faint,  it  seems  probable  that  an  indef 
inite  number,  too  small  for  detection,  may  be  constantly 
traversing  the  solar  domain.  If  we  adopt  Laplace's  hy 
pothesis  of  the  origin  of  comets,  we  may  suppose  an  almost 
continuous  fall  of  primitive  nebular  matter  toward  the  cen 
ter  of  the  system — the  drops  of  which,  penetrating  the 
earth's  atmosphere,  produce  sporadic  meteors ;  the  larger 
aggregations  forming  comets.  The  disturbing  influence  of 
the  planets  may  have  transformed  the  original  orbits  of 
many  of  the  former,  as  well  as  of  the  latter,  into  ellipses. 
It  is  an  interesting  fact  that  the  motions  of  some  luminous 
meteors — or  cometoids,  as  perhaps  they  might  be  called — 
have  been  decidedly  indicative  of  an  origin  beyond  the 
limits  of  the  planetary  system. 

"  But  how  are  the  phenomena  of  periodic  meteors  to  be 
accounted  for,  in  accordance  with  this  theory  ? 

"  The  division  of  Biela's  comet  into  two  distinct  parts 
suggests  several  interesting  questions  in  cometary  physics. 
The  nature  of  the  separating  force  remains  to  be  discovered ; 
'  but  it  is  impossible  to  doubt  that  it  arose  from  the  divellent 
action  of  the  sun,  whatever  may  have  been  the  mode  of 
operation.' 

"  'A  signal  manifestation  of  the  influence  of  the  sun,'  says 
a  distinguished  writer,  Ms  sometimes  afforded  by  the  break- 


APPENDIX.  127 

ing  up  of  a  comet  into  two  or  more  separate  parts,  on  the 
occasion  of  its  approach  to  the  perihelion.  Seneca  relates 
that  Ephoras,  an  ancient  Greek  author,  makes  mention- of  a 
comet  which  before  vanishing  was  seen  to  divide  itself  into 
two  distinct  bodies.  The  Roman  philosopher  appears  to 
doubt  the  possibility  of  such  a  fact;  but  Keppler,  with 
characteristic  sagacity,  has  remarked  that  its  actual  occur 
rence  was  exceedingly  probable.  The  latter  astronomer 
further  remarked  that  there  were  some  grounds  for  suppos 
ing  that  two  comets,  which  appeared  in  the  same  region  of 
the  heavens  in  the  year  1618,  were  the  fragments  of  a  comet 
that  had  experienced  a  similar  dissolution.  Hevelius  states 
that  Cysatus  perceived  in  the  head  of  the  great  comet  of 
1G18  unequivocal  symptoms  of  a  breaking  up  of  the  body 
into  distinct  fragments.  The  comet  when  first  seen  in  the 
month  of  November,  appeared  like  a  round  mass  of  con 
centrated  light.  On  the  8th  of  December  it  seemed  to  be 
divided  into  several  parts.  On  the  20th  of  the  same  month 
it  resembled  a  multitude  of  small  stars.  Hevelius  states 
that  he  himself  witnessed  a  similar  appearance  in  the  head 
of  the  comet  of  1661.'*  Edward  Biot,  moreover,  in  his 
researches  among  the  Chinese  records,  found  an  account  of 
'three  dome-formed  comets'  that  were  visible  simultane 
ously  in  896,  and  pursued  very  nearly  the  same  apparent 
path. 

"Another  instance  of  a  similar  phenomenon  is  recorded 
by  Dion  Cassius,  who  states  that  a  comet  which  appeared 
eleven  years  before  our  era,  separated  itself  into  several 
small  comets. 

"  These  various  examples  are  presented  at  one  view,  as 
follows : 

"  I.  Ancient  bipartition  of  a  comet. — Seneca,  Qusest.  Nat., 
lib.  VII.  cap.  XVI. 

*  Grant's  Hist,  of  Phys.  Astr.,  p.  302. 


128  APPENDIX. 

"  II.  Separation  of  a  comet  into  a  number  of  fragments, 
11  B.C. — Dion  Cassius. 

"  III.  Three  comets  seen  simultaneously  pursuing  the 
same  orbit,  A.D.  896 — Chinese  records — Comptes 
JRendus,  torn.  xx.  1845,  p.  334. 

"IV.  Probable  separation  of  a  comet  into  parts,  A.D. 
1618. — Hevelius,  Cometographia,  p.  341. — Kep- 
pler,  De  Cometis,  p.  50. 

"V.  Indications  of  separation,  1661. — Hevelius  Cometo 
graphia,  p.  41 1. 

"VI.  Bipartition  of  Biela's  comet,  1845-6. 

"  In  view  of  these  facts  it  seems  highly  probable,  if  not 
absolutely  certain,  that  the  process  of  division  has  taken 
place  in  several  instances  besides  that  of  Biela's  comet. 
May  not  the  force,  whatever  it  is,  that  has  produced  one 
separation,  again  divide  the  parts?  And  may  not  this 
action  continue  until  the  fragments  become  invisible?  Ac 
cording  to  the  theory  now  generally  received,  the  periodic 
phenomena  of  shooting-stars  are  produced  by  the  intersec 
tions  of  the  orbits  of  such  nebulous  bodies  with  the  earth's 
annual  path.  Now  there  is  reason  to  believe  that  these 
meteoric  rings  are  very  elliptical,  and  in  this  respect  wholly 
dissimilar  to  the  rings  of  primitive  vapor  which,  according 
to  the  nebular  hypothesis,  were  successively  abandoned  at 
the  solar  equator  ;  in  other  words,  that  the  matter  of  which 
they  are  composed  moves  in  cometary  rather  th&u  planetary 
orbits.  May  not  our  periodic  meteors  be  the  debris  of  an 
cient  but  now  disintegrated  comets,  whose  matter  has 
become  distributed  around  their  orbits?" 


APPENDIX.  129 


C. 

Biela's  Comet  and  the  Meteors  of  November  27th-30th. 

At  the  close  of  Chapter  IY.  it  was  suggested  that  the 
meteors  of  November  2Tth-30th  might  possibly  be  derived 
from  a  ring  of  meteoric  matter  moving  in  the  orbit  of  Biela's 
comet.  Since  that  chapter  was  written  similar  conjectures 
have  been  started  in  the  Astronomixche  Nachricliten*  by 
Dr.  Edmund  Weiss  and  Prof.  d'Arrest.  The  latter  attempts 
to  show  that  the  December  meteors  may  be  derived  from 
the  same  ring.  The  question  will  doubtless  bo  decided  at 
no  distant  day. 


IX 

The  First  Comet  of  1861  and  the  Meteors  of  April  20th. 

Recent  investigations  render  it  probable  that  the  orbit  of 
the  first  comet  of  18G1  is  identical  with  that  of  the  meteors 
of  April  20th.  The  orbit  is  nearly  perpendicular  to  the 
ecliptic. 


*  Nos.  1632  and  1033. 


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Amateurs  and  Artists.  By  G.  W.  SAMSON,  D.D.,  President  of 
Columbian  College,  Washington,  D.  C.  Second  Edition.  Crown 
8vo.  Cloth.  Price  $3.50. 

This  work  comprises  a  Treatise  on  the  Principles  of  Man's 
Nature  as  addressed  by  Art,  together  with  a  Historic  survey  of  the 
Methods  of  Art  Execution  in  the  departments  of  Drawing,  Sculp 
ture,  Architecture,  Painting,  Landscape  Gardening,  and  the  Dec 
orative  Arts.  The  Round  Table  says :  "  The  work  is  incontestably 
one  of  great  as  well  as  unique  value." 

HISTOEY  OF  THE  U.  S,  SANITAKY  COMMISSION, 

Being  the  General  Report  of  its  Work  on  the  War  of  the  Re 
bellion.  By  CHARLES  J.  STILLE,  Professor  in  the  University 
of  Pennsylvania.  One  vol.  8vo.  Cloth,  beveled  boards. 
Price  $3.50. 

TEEKA  MAEIJE  ;  or,  Threads  of  Maryland  Colonial  History, 
By  EDWARD  D.  NEILL,  one  of  the  Secretaries  of  the  President 
of  the  United  States.     12mo.     Extra  Cloth.     Price  $2.00. 

COMING  "WONDEES,  expected  between  1867  and  1875, 
By  the  Rev.  M.  BAXTER,  author  of  "The  Coming  Battle."     One 
vol.  12mo.     Cloth.     Price  $1.00. 


PUBLICATIONS  OP  J,  B,  LIPPINCOTT  &  00, 

Will  be  sent  by  Mail  on  receipt  of  price. 

LIPPINCOTT' S  PRONOUNCING  GAZET 
TEER   OF  THE  WORLD, 

OR  GEOGRAPHICAL  DICTIONARY. 

Revised  Edition,  with  an  Appendix  containing  nearly  ten 
thousand  new  notices,  and  the  most  recent  Statistical  Informa 
tion,  according  to  the  latest  Census  Returns,  of  the  United 
States  and  Foreign  Countries. 

Lippincott's  Pronouncing  Gazetteer  gives— 

I. — A  Descriptive  notice  of  the  Countries,  Islands,  Rivers, 
Mountains,  Cities,  Towns,  etc.,  in  every  part  of  the  Globe, 
with  the  most  Recent  and  Authentic  Information. 

II. — The  Names  of  all  Important  places,  etc.,  both  in  their 
Native  and  Foreign  Languages,  with  the  PRONUNCIATION 
of  the  same — a  Feature  never  attempted  in  any  other  Work. 

III. — The  Classical  Names  of  all  Ancient  Places,  so  far  as 
they  can  be  accurately  ascertained  from  the  best  Authori 
ties. 

IV. — A  Complete  Etymological  Vocabulary  of  Geographical 
Names. 

V. — An  elaborate  Introduction,  explanatory  of  the  Principles 
of  Pronunciation  of  Names  in  the  Danish,  Dutch,  French, 
German,  Greek,  Hungarian,  Italian,  Norwegian,  Polish, 
Portuguese,  Russian,  Spanish,  Swedish,  and  Welsh  Lan 
guages. 

Comprised  in  a  volume  of  over  two  thousand  three  hundred 
imperial  octavo  pages.  Price,  $10.00. 

FROM  THE  HON.  HORACE  MANN,  LL.D., 
Late  President  of  Antioch  College. 

I  have  had  your  Pronouncing  Gazetteer  of  the  World  before  me 
for  some  weeks.  Having  long  felt  the  necessity  of  a  work  of  this 
kind,  I  have  spent  no  small  amount  of  time  in  examining  yours.  It 
seems  to  me  so  important  to  have  a  comprehensive  and  authentic 
gazetteer  in  all  our  colleges,  academies,  and  schools,  that  I  am  in 
duced  in  this  instance  to  depart  from  my  general  rule  in  regard  to 
giving  recommendations.  Your  work  has  evidently  been  prepared 
with  immense  labor;  and  it  exhibits  proofs  from  beginning  to  end 
that  knowledge  has  presided  over  its  execution.  The  rising  genera 
tion  will  be  greatly  benefited,  both  in  the  accuracy  and  extent  of 
their  information,  should  your  work  be  kept  as  a  book  of  reference 
on  the  table  of  every  professor  and  teacher  in  the  country. 


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